diff --git a/creator-keys/src/lib.rs b/creator-keys/src/lib.rs
index 06d60c9..13e41f3 100644
--- a/creator-keys/src/lib.rs
+++ b/creator-keys/src/lib.rs
@@ -179,8 +179,10 @@ impl CreatorKeysContract {
             .ok_or(ContractError::Overflow)?;
         env.storage().persistent().set(&balance_key, &new_balance);
 
-        env.events()
-            .publish((symbol_short!("buy"), creator, buyer), profile.supply);
+        env.events().publish(
+            (symbol_short!("buy"), creator, buyer),
+            (profile.supply, payment),
+        );
 
         Ok(profile.supply)
     }
diff --git a/creator-keys/tests/buy_key_event.rs b/creator-keys/tests/buy_key_event.rs
new file mode 100644
index 0000000..5ce2558
--- /dev/null
+++ b/creator-keys/tests/buy_key_event.rs
@@ -0,0 +1,59 @@
+//! Tests verifying that the buy-key event includes the payment amount.
+
+use creator_keys::{CreatorKeysContract, CreatorKeysContractClient};
+use soroban_sdk::{symbol_short, testutils::Address as _, testutils::Events, Env, IntoVal, String};
+
+#[test]
+fn test_buy_key_event_includes_payment_amount() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    let contract_id = env.register(CreatorKeysContract, ());
+    let client = CreatorKeysContractClient::new(&env, &contract_id);
+
+    let admin = soroban_sdk::Address::generate(&env);
+    let creator = soroban_sdk::Address::generate(&env);
+    let buyer = soroban_sdk::Address::generate(&env);
+
+    client.set_key_price(&admin, &100i128);
+    client.register_creator(&creator, &String::from_str(&env, "alice"));
+    let supply = client.buy_key(&creator, &buyer, &150i128);
+    assert_eq!(supply, 1);
+
+    let events = env.events().all();
+    // Last event is the buy event
+    let buy_event = events.last().unwrap();
+    // Data is (supply, payment)
+    let (event_supply, event_payment): (u32, i128) = buy_event.2.into_val(&env);
+    assert_eq!(event_supply, 1u32);
+    assert_eq!(event_payment, 150i128);
+}
+
+#[test]
+fn test_buy_key_event_topics_include_creator_and_buyer() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    let contract_id = env.register(CreatorKeysContract, ());
+    let client = CreatorKeysContractClient::new(&env, &contract_id);
+
+    let admin = soroban_sdk::Address::generate(&env);
+    let creator = soroban_sdk::Address::generate(&env);
+    let buyer = soroban_sdk::Address::generate(&env);
+
+    client.set_key_price(&admin, &100i128);
+    client.register_creator(&creator, &String::from_str(&env, "alice"));
+    client.buy_key(&creator, &buyer, &200i128);
+
+    let events = env.events().all();
+    let buy_event = events.last().unwrap();
+
+    // Topics: (symbol "buy", creator address, buyer address)
+    let topic_symbol: soroban_sdk::Symbol = buy_event.1.get(0).unwrap().into_val(&env);
+    let topic_creator: soroban_sdk::Address = buy_event.1.get(1).unwrap().into_val(&env);
+    let topic_buyer: soroban_sdk::Address = buy_event.1.get(2).unwrap().into_val(&env);
+
+    assert_eq!(topic_symbol, symbol_short!("buy"));
+    assert_eq!(topic_creator, creator);
+    assert_eq!(topic_buyer, buyer);
+}
diff --git a/creator-keys/tests/events.rs b/creator-keys/tests/events.rs
index 5896df9..4f12f0d 100644
--- a/creator-keys/tests/events.rs
+++ b/creator-keys/tests/events.rs
@@ -96,19 +96,21 @@ fn test_buy_key_event_data_is_new_supply() {
 
     client.register_creator(&creator, &String::from_str(&env, "alice"));
 
-    // First buy → supply = 1
+    // First buy → supply = 1, payment = 100
     client.buy_key(&creator, &buyer1, &100_i128);
     let events = env.events().all();
     let (_, _, data) = events.last().unwrap();
-    let supply: u32 = data.into_val(&env);
+    let (supply, payment): (u32, i128) = data.into_val(&env);
     assert_eq!(supply, 1);
+    assert_eq!(payment, 100);
 
-    // Second buy → supply = 2
+    // Second buy → supply = 2, payment = 100
     client.buy_key(&creator, &buyer2, &100_i128);
     let events = env.events().all();
     let (_, _, data) = events.last().unwrap();
-    let supply: u32 = data.into_val(&env);
+    let (supply, payment): (u32, i128) = data.into_val(&env);
     assert_eq!(supply, 2);
+    assert_eq!(payment, 100);
 }
 
 #[test]