diff --git a/packages/api/config/signed-api.example.json b/packages/api/config/signed-api.example.json
index ead93b3c..c56a5852 100644
--- a/packages/api/config/signed-api.example.json
+++ b/packages/api/config/signed-api.example.json
@@ -9,5 +9,5 @@
       "delaySeconds": 15
     }
   ],
-  "allowedAirnodes": ["0x8A791620dd6260079BF849Dc5567aDC3F2FdC318"]
+  "allowedAirnodes": ["0xbF3137b0a7574563a23a8fC8badC6537F98197CC"]
 }
diff --git a/packages/api/package.json b/packages/api/package.json
index 046e734b..8f83a2de 100644
--- a/packages/api/package.json
+++ b/packages/api/package.json
@@ -9,7 +9,7 @@
   "scripts": {
     "build": "tsc --project tsconfig.build.json",
     "clean": "rm -rf coverage dist",
-    "dev": "nodemon --ext ts,js,json,env --exec \"pnpm ts-node src/dev-server.ts\"",
+    "dev": "nodemon --ext ts,js,json,env --exec \"DEV_SERVER_PORT=${DEV_SERVER_PORT:-8090} pnpm ts-node src/dev-server.ts\"",
     "docker:build": "docker build --target api --tag api3/signed-api:latest ../../",
     "docker:run": "docker run --publish 8090:80 -it --init --volume $(pwd)/config:/app/config --env-file .env --rm api3/signed-api:latest",
     "eslint:check": "eslint . --ext .js,.ts --max-warnings 0",
diff --git a/packages/api/src/dev-server.ts b/packages/api/src/dev-server.ts
index 1249bcd4..f9909b36 100644
--- a/packages/api/src/dev-server.ts
+++ b/packages/api/src/dev-server.ts
@@ -4,7 +4,7 @@ import { fetchAndCacheConfig } from './config';
 import { logger } from './logger';
 import { DEFAULT_PORT, startServer } from './server';
 
-const portSchema = z.number().int().positive();
+const portSchema = z.coerce.number().int().positive();
 
 const startDevServer = async () => {
   const config = await fetchAndCacheConfig();
diff --git a/packages/api/src/handlers.test.ts b/packages/api/src/handlers.test.ts
index 211a432e..2a104623 100644
--- a/packages/api/src/handlers.test.ts
+++ b/packages/api/src/handlers.test.ts
@@ -1,3 +1,4 @@
+import { ethers } from 'ethers';
 import { omit } from 'lodash';
 
 import { getMockedConfig } from '../test/fixtures';
@@ -27,9 +28,11 @@ describe(batchInsertData.name, () => {
     expect(result).toStrictEqual({
       body: JSON.stringify({
         message: 'Unable to recover signer address',
-        detail:
-          'signature missing v and recoveryParam (argument="signature", value="0xInvalid", code=INVALID_ARGUMENT, version=bytes/5.7.0)',
-        extra: invalidData,
+        context: {
+          detail:
+            'signature missing v and recoveryParam (argument="signature", value="0xInvalid", code=INVALID_ARGUMENT, version=bytes/5.7.0)',
+          signedData: invalidData,
+        },
       }),
       headers: {
         'access-control-allow-methods': '*',
@@ -45,12 +48,18 @@ describe(batchInsertData.name, () => {
     const config = getMockedConfig();
     config.allowedAirnodes = [];
     jest.spyOn(configModule, 'getConfig').mockReturnValue(config);
-    const batchData = [await createSignedData()];
+    const airnodeWallet = ethers.Wallet.fromMnemonic(
+      'wear lawsuit design cry express certain knock shrug credit wealth update walk'
+    );
+    const batchData = [await createSignedData({ airnodeWallet })];
 
     const result = await batchInsertData(batchData);
 
     expect(result).toStrictEqual({
-      body: JSON.stringify({ message: 'Unauthorized Airnode address' }),
+      body: JSON.stringify({
+        message: 'Unauthorized Airnode address',
+        context: { airnodeAddress: '0x05E4B3cb2A6875bdD4CCb867B6aA833934EDDCBf' },
+      }),
       headers: {
         'access-control-allow-methods': '*',
         'access-control-allow-origin': '*',
@@ -103,7 +112,10 @@ describe(batchInsertData.name, () => {
     const result = await batchInsertData(batchData);
 
     expect(result).toStrictEqual({
-      body: JSON.stringify({ message: 'Request timestamp is too far in the future', extra: batchData[0] }),
+      body: JSON.stringify({
+        message: 'Request timestamp is too far in the future',
+        context: { signedData: batchData[0] },
+      }),
       headers: {
         'access-control-allow-methods': '*',
         'access-control-allow-origin': '*',
diff --git a/packages/api/src/handlers.ts b/packages/api/src/handlers.ts
index 505bfcca..5892509a 100644
--- a/packages/api/src/handlers.ts
+++ b/packages/api/src/handlers.ts
@@ -18,11 +18,9 @@ import { generateErrorResponse, isBatchUnique } from './utils';
 export const batchInsertData = async (requestBody: unknown): Promise<ApiResponse> => {
   const goValidateSchema = await go(async () => batchSignedDataSchema.parseAsync(requestBody));
   if (!goValidateSchema.success) {
-    return generateErrorResponse(
-      400,
-      'Invalid request, body must fit schema for batch of signed data',
-      goValidateSchema.error.message
-    );
+    return generateErrorResponse(400, 'Invalid request, body must fit schema for batch of signed data', {
+      detail: goValidateSchema.error.message,
+    });
   }
 
   // Ensure that the batch of signed that comes from a whitelisted Airnode.
@@ -31,7 +29,10 @@ export const batchInsertData = async (requestBody: unknown): Promise<ApiResponse
     allowedAirnodes !== '*' &&
     !goValidateSchema.data.every((signedData) => allowedAirnodes.includes(signedData.airnode))
   ) {
-    return generateErrorResponse(403, 'Unauthorized Airnode address');
+    const disallowedAirnodeAddress = goValidateSchema.data.find(
+      (signedData) => !allowedAirnodes.includes(signedData.airnode)
+    )!.airnode;
+    return generateErrorResponse(403, 'Unauthorized Airnode address', { airnodeAddress: disallowedAirnodeAddress });
   }
 
   // Ensure there is at least one signed data to push
@@ -46,30 +47,31 @@ export const batchInsertData = async (requestBody: unknown): Promise<ApiResponse
     // The on-chain contract prevents time drift by making sure the timestamp is at most 1 hour in the future. System
     // time drift is less common, but we mirror the contract implementation.
     if (Number.parseInt(signedData.timestamp, 10) > Math.floor(Date.now() / 1000) + 60 * 60) {
-      return generateErrorResponse(400, 'Request timestamp is too far in the future', undefined, signedData);
+      return generateErrorResponse(400, 'Request timestamp is too far in the future', { signedData });
     }
 
     const goRecoverSigner = goSync(() => recoverSignerAddress(signedData));
     if (!goRecoverSigner.success) {
-      return generateErrorResponse(400, 'Unable to recover signer address', goRecoverSigner.error.message, signedData);
+      return generateErrorResponse(400, 'Unable to recover signer address', {
+        detail: goRecoverSigner.error.message,
+        signedData,
+      });
     }
 
     if (signedData.airnode !== goRecoverSigner.data) {
-      return generateErrorResponse(400, 'Signature is invalid', undefined, signedData);
+      return generateErrorResponse(400, 'Signature is invalid', { signedData });
     }
 
     const goDeriveBeaconId = goSync(() => deriveBeaconId(signedData.airnode, signedData.templateId));
     if (!goDeriveBeaconId.success) {
-      return generateErrorResponse(
-        400,
-        'Unable to derive beaconId by given airnode and templateId',
-        goDeriveBeaconId.error.message,
-        signedData
-      );
+      return generateErrorResponse(400, 'Unable to derive beaconId by given airnode and templateId', {
+        detail: goDeriveBeaconId.error.message,
+        signedData,
+      });
     }
 
     if (signedData.beaconId !== goDeriveBeaconId.data) {
-      return generateErrorResponse(400, 'beaconId is invalid', undefined, signedData);
+      return generateErrorResponse(400, 'beaconId is invalid', { signedData });
     }
 
     return null;
@@ -96,7 +98,9 @@ export const batchInsertData = async (requestBody: unknown): Promise<ApiResponse
   // Write batch of validated data to the database
   const goBatchWriteDb = await go(async () => putAll(newSignedData));
   if (!goBatchWriteDb.success) {
-    return generateErrorResponse(500, 'Unable to send batch of signed data to database', goBatchWriteDb.error.message);
+    return generateErrorResponse(500, 'Unable to send batch of signed data to database', {
+      detail: goBatchWriteDb.error.message,
+    });
   }
 
   // Prune the cache with the data that is too old (no endpoint will ever return it)
@@ -104,7 +108,7 @@ export const batchInsertData = async (requestBody: unknown): Promise<ApiResponse
   const maxIgnoreAfterTimestamp = Math.floor(Date.now() / 1000 - maxDelay);
   const goPruneCache = await go(async () => prune(newSignedData, maxIgnoreAfterTimestamp));
   if (!goPruneCache.success) {
-    return generateErrorResponse(500, 'Unable to remove outdated cache data', goPruneCache.error.message);
+    return generateErrorResponse(500, 'Unable to remove outdated cache data', { detail: goPruneCache.error.message });
   }
 
   return {
@@ -130,13 +134,13 @@ export const getData = async (airnodeAddress: string, delaySeconds: number): Pro
 
   const { allowedAirnodes } = getConfig();
   if (allowedAirnodes !== '*' && !allowedAirnodes.includes(airnodeAddress)) {
-    return generateErrorResponse(403, 'Unauthorized Airnode address');
+    return generateErrorResponse(403, 'Unauthorized Airnode address', { airnodeAddress });
   }
 
   const ignoreAfterTimestamp = Math.floor(Date.now() / 1000 - delaySeconds);
   const goReadDb = await go(async () => getAll(airnodeAddress, ignoreAfterTimestamp));
   if (!goReadDb.success) {
-    return generateErrorResponse(500, 'Unable to get signed data from database', goReadDb.error.message);
+    return generateErrorResponse(500, 'Unable to get signed data from database', { detail: goReadDb.error.message });
   }
 
   const data = goReadDb.data.reduce((acc, signedData) => {
@@ -156,7 +160,7 @@ export const getData = async (airnodeAddress: string, delaySeconds: number): Pro
 export const listAirnodeAddresses = async (): Promise<ApiResponse> => {
   const goAirnodeAddresses = await go(async () => getAllAirnodeAddresses());
   if (!goAirnodeAddresses.success) {
-    return generateErrorResponse(500, 'Unable to scan database', goAirnodeAddresses.error.message);
+    return generateErrorResponse(500, 'Unable to scan database', { detail: goAirnodeAddresses.error.message });
   }
   const airnodeAddresses = goAirnodeAddresses.data;
 
diff --git a/packages/api/src/utils.ts b/packages/api/src/utils.ts
index 6d21a6d1..e19bcf88 100644
--- a/packages/api/src/utils.ts
+++ b/packages/api/src/utils.ts
@@ -15,8 +15,11 @@ export const isIgnored = (signedData: SignedData, ignoreAfterTimestamp: number)
 export const generateErrorResponse = (
   statusCode: number,
   message: string,
-  detail?: string,
-  extra?: unknown
+  context?: Record<string, unknown>
 ): ApiResponse => {
-  return { statusCode, headers: createResponseHeaders(), body: JSON.stringify({ message, detail, extra }) };
+  return {
+    statusCode,
+    headers: createResponseHeaders(),
+    body: JSON.stringify(context ? { message, context } : { message }),
+  };
 };