diff --git a/backend/src/index.test.ts b/backend/src/index.test.ts
index 2211454..54cbe94 100644
--- a/backend/src/index.test.ts
+++ b/backend/src/index.test.ts
@@ -568,6 +568,3 @@ describe("GET /api/events", () => {
   });
 });
 
-
-  });
-});
diff --git a/backend/src/index.ts b/backend/src/index.ts
index 55691e6..d5fc066 100644
--- a/backend/src/index.ts
+++ b/backend/src/index.ts
@@ -18,7 +18,7 @@ import {
   getStreamHistory,
 } from "./services/eventHistory";
 import { fetchOpenIssues } from "./services/openIssues";
-import { initIndexer, startIndexer } from "./services/indexer";
+import { initIndexer, startIndexer, getCircuitBreakerStatus } from "./services/indexer";
 import { startReconciliationJob } from "./services/reconciliationJob";
 import { startWebhookWorker } from "./services/webhookWorker";
 import { getDeadLetters, countDeadLetters } from "./services/webhook";
@@ -35,12 +35,7 @@ import {
   syncStreams,
   updateStreamStartAt,
 } from "./services/streamStore";
-import {
-  getGlobalEvents,
-  countAllEvents,
-  getStreamHistory,
-  getAllEvents,
-} from "./services/eventHistory";
+
 import {
   authMiddleware,
   generateChallenge,
@@ -138,6 +133,12 @@ app.get("/api/health", (_req: Request, res: Response) => {
   });
 });
 
+app.get("/api/metrics", (_req: Request, res: Response) => {
+  res.json({
+    indexer_circuit_breaker: getCircuitBreakerStatus(),
+  });
+});
+
 app.get("/api/assets", (_req: Request, res: Response) => {
   res.json({
     data: ALLOWED_ASSETS,
@@ -313,7 +314,7 @@ app.get("/api/recipients/:accountId/streams", (req: Request, res: Response) => {
 
   const parsedQuery = listStreamsQuerySchema.safeParse(req.query);
   if (!parsedQuery.success) {
-    sendValidationError(res, parsedQuery.error.issues);
+    sendValidationError(req, res, parsedQuery.error.issues);
     return;
   }
   const query = parsedQuery.data;
@@ -480,6 +481,7 @@ app.post("/api/streams", authMiddleware, async (req: Request, res: Response) =>
     return;
   }
 
+
   try {
     const stream = await createStream(parsedBody.data);
     res.status(201).json({
@@ -523,7 +525,12 @@ app.post(
     }
 
     try {
-
+      const canceledStream = await cancelStream(parsedId.value);
+      if (!canceledStream) {
+        res.status(404).json({ error: "Stream not found or could not be canceled.", requestId: req.requestId });
+        return;
+      }
+      res.json({ data: { ...canceledStream, progress: calculateProgress(canceledStream) } });
     } catch (error: any) {
       console.error("Failed to cancel stream:", error);
       const normalizedError = normalizeUnknownApiError(error, "Failed to cancel stream.");
@@ -568,26 +575,10 @@ app.patch(
       return;
     }
 
-    const stream = getStream(parsedId.value);
-    if (!stream) {
-      res.status(404).json({ error: "Stream not found.", requestId: req.requestId });
-      return;
-    }
-
-    const user = (req as any).user;
-    if (stream.sender !== user.accountId) {
-      res.status(403).json({
-        error: "Only the sender can update the start time.",
-        requestId: req.requestId,
-      });
-      return;
-    }
-
     const now = Math.floor(Date.now() / 1000);
     const newStartAt = parsedBody.data.startAt;
 
-    return;
-  }
+
 
     try {
   const updatedStream = updateStreamStartAt(parsedId.value, newStartAt);
diff --git a/backend/src/services/auth.ts b/backend/src/services/auth.ts
index b669c27..4f3a832 100644
--- a/backend/src/services/auth.ts
+++ b/backend/src/services/auth.ts
@@ -81,7 +81,7 @@ export function verifyChallengeAndIssueToken(
       );
     }
 
-    const token = jwt.sign({ accountId: clientAccountID }, JWT_SECRET, {
+    const token = jwt.sign({ accountId: clientAccountID }, getJwtSecret(), {
       expiresIn: "24h",
     });
     return token;
@@ -104,7 +104,6 @@ export function authMiddleware(
   if (!authHeader || !authHeader.startsWith("Bearer ")) {
     sendApiError(req, res, 401, "Missing or invalid authorization header.", {
       code: "UNAUTHORIZED",
-      requestId: (req as any).requestId,
     });
     return;
   }
@@ -118,7 +117,6 @@ export function authMiddleware(
   } catch (error) {
     sendApiError(req, res, 401, "Invalid or expired authorization token.", {
       code: "UNAUTHORIZED",
-      requestId: (req as any).requestId,
     });
   }
 }
diff --git a/backend/src/services/indexer.ts b/backend/src/services/indexer.ts
index 47463dd..980c00b 100644
--- a/backend/src/services/indexer.ts
+++ b/backend/src/services/indexer.ts
@@ -14,6 +14,69 @@ let networkPassphrase: string = Networks.TESTNET;
 let lastProcessedLedger = 0;
 let indexerInterval: NodeJS.Timeout | null = null;
 
+export enum CircuitState {
+  CLOSED = "CLOSED",
+  OPEN = "OPEN",
+  HALF_OPEN = "HALF_OPEN",
+}
+
+class CircuitBreaker {
+  private state: CircuitState = CircuitState.CLOSED;
+  private failureCount: number = 0;
+  private lastFailureTime: number = 0;
+  private readonly failureThreshold: number = 5;
+  private readonly timeoutMs: number;
+
+  constructor(timeoutMs: number = 60000) {
+    this.timeoutMs = timeoutMs;
+  }
+
+  public getState(): CircuitState {
+    if (this.state === CircuitState.OPEN) {
+      const now = Date.now();
+      if (now - this.lastFailureTime >= this.timeoutMs) {
+        this.setState(CircuitState.HALF_OPEN);
+      }
+    }
+    return this.state;
+  }
+
+  public onSuccess(): void {
+    if (this.state !== CircuitState.CLOSED) {
+      console.log(`[Circuit Breaker] Probe successful. Resetting to CLOSED state.`);
+      this.setState(CircuitState.CLOSED);
+    }
+    this.failureCount = 0;
+  }
+
+  public onFailure(): void {
+    this.failureCount++;
+    this.lastFailureTime = Date.now();
+    
+    if (this.state === CircuitState.CLOSED && this.failureCount >= this.failureThreshold) {
+      console.log(`[Circuit Breaker] ${this.failureThreshold} consecutive failures reached. Opening circuit.`);
+      this.setState(CircuitState.OPEN);
+    } else if (this.state === CircuitState.HALF_OPEN) {
+      console.log(`[Circuit Breaker] Probe failed in HALF_OPEN state. Re-opening circuit.`);
+      this.setState(CircuitState.OPEN);
+    }
+  }
+
+  private setState(newState: CircuitState): void {
+    if (this.state !== newState) {
+      console.log(`[Circuit Breaker] State Transition: ${this.state} -> ${newState}`);
+      this.state = newState;
+    }
+  }
+}
+
+const CIRCUIT_BREAKER_TIMEOUT_MS = Number(process.env.CIRCUIT_BREAKER_TIMEOUT_MS ?? 60000);
+const circuitBreaker = new CircuitBreaker(CIRCUIT_BREAKER_TIMEOUT_MS);
+
+export function getCircuitBreakerStatus(): CircuitState {
+  return circuitBreaker.getState();
+}
+
 export function initIndexer(
   rpcUrl: string,
   contractIdParam: string,
@@ -57,6 +120,11 @@ async function indexEvents(): Promise<void> {
     return;
   }
 
+  const state = circuitBreaker.getState();
+  if (state === CircuitState.OPEN) {
+    return;
+  }
+
   try {
     const db = getDb();
     const latestLedger = await rpcServer.getLatestLedger();
@@ -77,6 +145,7 @@ async function indexEvents(): Promise<void> {
     }
 
     if (currentLedger <= lastProcessedLedger) {
+      circuitBreaker.onSuccess();
       return;
     }
 
@@ -103,7 +172,10 @@ async function indexEvents(): Promise<void> {
         "INSERT INTO indexer_cursor (id, last_ledger) VALUES (?, ?) ON CONFLICT(id) DO UPDATE SET last_ledger = excluded.last_ledger",
       ).run(contractId, lastProcessedLedger);
     })();
+
+    circuitBreaker.onSuccess();
   } catch (err) {
+    circuitBreaker.onFailure();
     console.error("Failed to index events:", err);
   }
 }
diff --git a/backend/src/services/streamStore.ts b/backend/src/services/streamStore.ts
index 2fa899e..41985d5 100644
--- a/backend/src/services/streamStore.ts
+++ b/backend/src/services/streamStore.ts
@@ -8,6 +8,7 @@ import {
   TimeoutInfinite,
   TransactionBuilder,
   Networks,
+  Account,
 } from "@stellar/stellar-sdk";
 import { initDb, getDb } from "./db";
 import { recordEventWithDb } from "./eventHistory";
@@ -142,7 +143,7 @@ function round(value: number): number {
 function getSorobanContext():
   | {
       contract: Contract;
-      sourceAccountPromise: Promise<rpc.Api.GetAccountResponse>;
+      sourceAccountPromise: Promise<Account>;
     }
   | undefined {
   const contractId = process.env.CONTRACT_ID;
@@ -162,7 +163,7 @@ function getSorobanContext():
 
 async function simulateContractCall(
   contract: Contract,
-  sourceAccount: rpc.Api.GetAccountResponse,
+  sourceAccount: Account,
   method: string,
   ...args: any[]
 ): Promise<rpc.Api.SimulateTransactionResponse> {
@@ -183,7 +184,7 @@ async function simulateContractCall(
 
 async function fetchNextOnChainStreamId(
   contract: Contract,
-  sourceAccount: rpc.Api.GetAccountResponse,
+  sourceAccount: Account,
 ): Promise<number | null> {
   const simRes = await simulateContractCall(
     contract,
@@ -201,7 +202,7 @@ async function fetchNextOnChainStreamId(
 
 async function fetchOnChainStreamRecord(
   contract: Contract,
-  sourceAccount: rpc.Api.GetAccountResponse,
+  sourceAccount: Account,
   id: number,
 ): Promise<StreamRecord | null> {
   const simRes = await simulateContractCall(
diff --git a/backend/src/swagger.ts b/backend/src/swagger.ts
index 5ad8d86..3e85e0b 100644
--- a/backend/src/swagger.ts
+++ b/backend/src/swagger.ts
@@ -673,7 +673,8 @@ export const swaggerDocument = {
               },
             },
           },
-
+          "400": {
+            description: "Invalid request.",
             content: {
               "application/json": {
                 schema: {