feat: review the 200 and 400 http code

.env.http.example

@@ -23,6 +23,7 @@ OPERATOR_KEY_MAIN=               # Operator private key used to sign transaction
 # TXPOOL_API_ENABLED=true        # Enables txpool related methods
 # FILTER_API_ENABLED=true        # Enables filter related methods
 # ESTIMATE_GAS_THROWS=true       # If true, throws actual error reason during contract reverts
+# VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE=true # If true, returns HTTP 200 for JSON-RPC errors
 
 # ========== BATCH REQUESTS ==========
 # BATCH_REQUESTS_ENABLED=true    # Enable or disable batch requests

.github/workflows/acceptance-workflow.yml

@@ -10,6 +10,10 @@ on:
         required: false
         default: false
         type: boolean
+      valid_json_rpc_http_requests_status_code:
+        required: false
+        default: false
+        type: boolean
       envfile:
         required: false
         default: localAcceptance.env
@@ -104,6 +108,7 @@ jobs:
           GITHUB_PR_NUMBER: ${{ github.event.number }}
           GITHUB_REPOSITORY: ${{ github.repository }}
           OPERATOR_KEY: ${{ secrets.operator_key }}
+          VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE: "${{ inputs.valid_json_rpc_http_requests_status_code }}"
 
       - name: Upload Heap Snapshots
         if: ${{ !cancelled() }}
@@ -117,7 +122,7 @@ jobs:
         if: always()
         uses: actions/upload-artifact@330a01c490aca151604b8cf639adc76d48f6c5d4 # v5.0.0
         with:
-          name: Test Results (${{ inputs.testfilter }})
+          name: Test Results (${{ inputs.testfilter }})${{ inputs.valid_json_rpc_http_requests_status_code && ' 200' || '' }}
           path: test-*.xml
 
       - name: Upload coverage report

.github/workflows/acceptance.yml

@@ -38,10 +38,15 @@ jobs:
           - { name: 'Websocket Batch 3', testfilter: 'ws_batch3', test_ws_server: true }
           - { name: 'Cache Service', testfilter: 'cache-service' }
           - { name: 'Server Config', testfilter: 'serverconfig' }
+          - { name: 'Semantics and varying response status', testfilter: 'json_rpc_compliance' }
+          - name: "Semantics and default OK response status"
+            testfilter: "json_rpc_compliance"
+            valid_json_rpc_http_requests_status_code: true
     uses: ./.github/workflows/acceptance-workflow.yml
     with:
       testfilter: ${{ matrix.test.testfilter }}
       test_ws_server: ${{ matrix.test.test_ws_server || false }}
+      valid_json_rpc_http_requests_status_code: ${{ matrix.test.valid_json_rpc_http_requests_status_code || false }}
     secrets:
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
 

docs/configuration.md

@@ -133,6 +133,7 @@ Unless you need to set a non-default value, it is recommended to only populate o
 | `SERVER_HOST`                       | undefined                                                                                                                                                                                            | The hostname or IP address on which the server listens for incoming connections. If `SERVER_HOST` is not configured or left undefined (same as `0.0.0.0`), it permits external connections by default, offering more flexibility.                                                |
 | `SERVER_PORT`                       | "7546"                                                                                                                                                                                               | The RPC server port number to listen for requests on. Currently a static value defaulting to 7546. See [#955](https://github.com/hiero-ledger/hiero-json-rpc-relay/issues/955)                                                                                                   |
 | `SERVER_REQUEST_TIMEOUT_MS`         | "60000"                                                                                                                                                                                              | The time of inactivity allowed before a timeout is triggered and the socket is closed. See [NodeJs Server Timeout](https://nodejs.org/api/http.html#serversettimeoutmsecs-callback)                                                                                              |
+| `VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE` | "false"                                                                                                                                                                                              | Setting this flag to "true" will cause the JSON-RPC relay server to always return an HTTP 200 status code for errors that comply with the JSON-RPC API standard, when a correctly formed request following the standard is received.                                             |
 
 ## WS-Server
 

package.json

@@ -67,6 +67,7 @@
     "acceptancetest:rpc_api_schema_conformity": "c8 ts-mocha packages/server/tests/acceptance/index.spec.ts  -g '@api-conformity' --exit",
     "acceptancetest:serverconfig": "c8 ts-mocha packages/server/tests/acceptance/index.spec.ts  -g '@server-config' --exit",
     "acceptancetest:send_raw_transaction_extension": "c8 ts-mocha packages/server/tests/acceptance/index.spec.ts  -g '@sendRawTransactionExtension' --exit",
+    "acceptancetest:json_rpc_compliance": "c8 ts-mocha packages/server/tests/acceptance/index.spec.ts  -g '@json-rpc-compliance' --exit",
     "acceptancetest:debug": "c8 ts-mocha packages/server/tests/acceptance/index.spec.ts  -g '@debug' --exit",
     "acceptancetest:xts": "c8 ts-mocha packages/server/tests/acceptance/index.spec.ts  -g '@xts' --exit",
     "build": "npx lerna run build",

packages/config-service/src/services/globalConfig.ts

@@ -739,6 +739,11 @@ const _CONFIG = {
     required: false,
     defaultValue: 10,
   },
+  VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE: {
+    type: 'boolean',
+    required: false,
+    defaultValue: false,
+  },
 } as const satisfies { [key: string]: ConfigProperty }; // Ensures _CONFIG is read-only and conforms to the ConfigProperty structure
 
 export type ConfigKey = keyof typeof _CONFIG;

packages/server/src/compliance.ts

@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: Apache-2.0
+
+import { ConfigService } from '@hashgraph/json-rpc-config-service/dist/services';
+import { ParameterizedContext } from 'koa';
+
+interface IResponseContext {
+  body: {
+    jsonrpc: unknown;
+    id: unknown;
+    result?: unknown;
+    error?: { code: unknown; message: unknown };
+  };
+  status: number | undefined;
+}
+
+const VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE = ConfigService.get('VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE');
+
+const FALLBACK_RESPONSE_BODY = {
+  jsonrpc: '2.0',
+  id: null,
+  error: { code: -32600, message: 'Request body is empty; expected a JSON-RPC 2.0 request' },
+};
+
+export const INVALID_METHOD_RESPONSE_BODY = {
+  ...FALLBACK_RESPONSE_BODY,
+  error: { code: -32600, message: 'Invalid HTTP method: only POST is allowed' },
+};
+
+const makeSureBodyExistsAndCanBeChecked = (ctx: IResponseContext) => {
+  if (ctx.status === 200) return false;
+
+  if (!ctx.body) {
+    ctx.status = 400;
+    ctx.body = structuredClone(FALLBACK_RESPONSE_BODY);
+    return false;
+  }
+
+  if (Array.isArray(ctx.body)) {
+    ctx.status = 200;
+    return false;
+  }
+
+  if (typeof ctx.body !== 'object') {
+    ctx.status = 400;
+    ctx.body = structuredClone(FALLBACK_RESPONSE_BODY);
+    return false;
+  }
+  if (!ctx.body.jsonrpc) ctx.body.jsonrpc = FALLBACK_RESPONSE_BODY.jsonrpc;
+  if (!ctx.body.id) ctx.body.id = FALLBACK_RESPONSE_BODY.id;
+
+  return true;
+};
+
+/**
+ * Ensures a JSON-RPC response uses a valid JSON-RPC 2.0 structure.
+ * Normalizes missing or invalid fields for both single and batch responses.
+ * May update HTTP status depending on VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE.
+ *
+ * @param {IResponseContext & ParameterizedContext} ctx - Koa context containing status and body.
+ */
+export const jsonRpcComplianceLayer = (ctx: IResponseContext & ParameterizedContext) => {
+  if (!makeSureBodyExistsAndCanBeChecked(ctx)) return;
+  if (ctx.status === 400) {
+    if (!ctx.body.error?.code) ctx.body.error = structuredClone(FALLBACK_RESPONSE_BODY.error);
+    if (VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE) ctx.status = 200;
+  }
+};

packages/server/src/koaJsonRpc/index.ts

@@ -124,11 +124,13 @@ export default class KoaJsonRpc {
 
     // verify max batch size
     if (body.length > this.batchRequestsMaxSize) {
-      ctx.body = jsonRespError(
-        null,
-        predefined.BATCH_REQUESTS_AMOUNT_MAX_EXCEEDED(body.length, this.batchRequestsMaxSize),
-        requestId,
-      );
+      ctx.body = [
+        jsonRespError(
+          null,
+          predefined.BATCH_REQUESTS_AMOUNT_MAX_EXCEEDED(body.length, this.batchRequestsMaxSize),
+          requestId,
+        ),
+      ];
       ctx.status = 400;
       ctx.state.status = `${ctx.status} (${INVALID_REQUEST})`;
       return;

packages/server/src/server.ts

@@ -12,6 +12,7 @@ import pino from 'pino';
 import { collectDefaultMetrics, Histogram, Registry } from 'prom-client';
 import { v4 as uuid } from 'uuid';
 
+import { INVALID_METHOD_RESPONSE_BODY, jsonRpcComplianceLayer } from './compliance';
 import { formatRequestIdMessage } from './formatters';
 import KoaJsonRpc from './koaJsonRpc';
 import { spec } from './koaJsonRpc/lib/RpcError';
@@ -277,7 +278,8 @@ export async function initializeServer() {
       // support CORS preflight
       ctx.status = 200;
     } else {
-      logger.warn(`skipping HTTP method: [${ctx.method}], url: ${ctx.url}, status: ${ctx.status}`);
+      ctx.status = ConfigService.get('VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE') ? 200 : 400;
+      ctx.body = structuredClone(INVALID_METHOD_RESPONSE_BODY);
     }
   });
 
@@ -309,6 +311,7 @@ export async function initializeServer() {
 
   app.use(async (ctx) => {
     await rpcApp(ctx);
+    jsonRpcComplianceLayer(ctx);
   });
 
   process.on('unhandledRejection', (reason, p) => {