diff --git a/packages/api/src/beacon/server/beacon.ts b/packages/api/src/beacon/server/beacon.ts
index b5862f766b56..a4d94b711785 100644
--- a/packages/api/src/beacon/server/beacon.ts
+++ b/packages/api/src/beacon/server/beacon.ts
@@ -3,7 +3,7 @@ import {Api, ReqTypes, routesData, getReturnTypes, getReqSerializers} from "../r
 import {ServerRoutes, getGenericJsonServer} from "../../utils/server/index.js";
 import {ServerApi} from "../../interfaces.js";
 
-export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<Api, ReqTypes> {
+export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<ServerApi<Api>, ReqTypes> {
   // All routes return JSON, use a server auto-generator
   return getGenericJsonServer<ServerApi<Api>, ReqTypes>({routesData, getReturnTypes, getReqSerializers}, config, api);
 }
diff --git a/packages/api/src/beacon/server/config.ts b/packages/api/src/beacon/server/config.ts
index 26d78ab9a5f1..39c87199465f 100644
--- a/packages/api/src/beacon/server/config.ts
+++ b/packages/api/src/beacon/server/config.ts
@@ -3,7 +3,7 @@ import {Api, ReqTypes, routesData, getReturnTypes, getReqSerializers} from "../r
 import {ServerRoutes, getGenericJsonServer} from "../../utils/server/index.js";
 import {ServerApi} from "../../interfaces.js";
 
-export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<Api, ReqTypes> {
+export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<ServerApi<Api>, ReqTypes> {
   // All routes return JSON, use a server auto-generator
   return getGenericJsonServer<ServerApi<Api>, ReqTypes>({routesData, getReturnTypes, getReqSerializers}, config, api);
 }
diff --git a/packages/api/src/beacon/server/debug.ts b/packages/api/src/beacon/server/debug.ts
index 7dd767d4a2fd..bc5c1b9829db 100644
--- a/packages/api/src/beacon/server/debug.ts
+++ b/packages/api/src/beacon/server/debug.ts
@@ -3,7 +3,7 @@ import {Api, ReqTypes, routesData, getReturnTypes, getReqSerializers} from "../r
 import {ServerRoutes, getGenericJsonServer} from "../../utils/server/index.js";
 import {ServerApi} from "../../interfaces.js";
 
-export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<Api, ReqTypes> {
+export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<ServerApi<Api>, ReqTypes> {
   const reqSerializers = getReqSerializers();
   const returnTypes = getReturnTypes();
 
@@ -21,11 +21,12 @@ export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerR
       ...serverRoutes.getState,
       handler: async (req) => {
         const response = await api.getState(...reqSerializers.getState.parseReq(req));
-        if (response instanceof Uint8Array) {
+        const res = "status" in response ? response.response : response;
+        if (res instanceof Uint8Array) {
           // Fastify 3.x.x will automatically add header `Content-Type: application/octet-stream` if Buffer
-          return Buffer.from(response);
+          return Buffer.from(res);
         } else {
-          return returnTypes.getState.toJson(response);
+          return returnTypes.getState.toJson(res);
         }
       },
     },
@@ -33,11 +34,12 @@ export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerR
       ...serverRoutes.getStateV2,
       handler: async (req) => {
         const response = await api.getStateV2(...reqSerializers.getStateV2.parseReq(req));
-        if (response instanceof Uint8Array) {
+        const res = "status" in response ? response.response : response;
+        if (res instanceof Uint8Array) {
           // Fastify 3.x.x will automatically add header `Content-Type: application/octet-stream` if Buffer
-          return Buffer.from(response);
+          return Buffer.from(res);
         } else {
-          return returnTypes.getStateV2.toJson(response);
+          return returnTypes.getStateV2.toJson(res);
         }
       },
     },
diff --git a/packages/api/src/beacon/server/events.ts b/packages/api/src/beacon/server/events.ts
index fa8b857f8779..fb700c51dde9 100644
--- a/packages/api/src/beacon/server/events.ts
+++ b/packages/api/src/beacon/server/events.ts
@@ -4,7 +4,7 @@ import {Api, ReqTypes, routesData, getEventSerdes} from "../routes/events.js";
 import {ServerRoutes} from "../../utils/server/index.js";
 import {ServerApi} from "../../interfaces.js";
 
-export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<Api, ReqTypes> {
+export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<ServerApi<Api>, ReqTypes> {
   const eventSerdes = getEventSerdes(config);
 
   return {
diff --git a/packages/api/src/beacon/server/lightclient.ts b/packages/api/src/beacon/server/lightclient.ts
index d587ec29823d..fdb2d5c5d0f2 100644
--- a/packages/api/src/beacon/server/lightclient.ts
+++ b/packages/api/src/beacon/server/lightclient.ts
@@ -3,7 +3,7 @@ import {Api, ReqTypes, routesData, getReturnTypes, getReqSerializers} from "../r
 import {ServerRoutes, getGenericJsonServer} from "../../utils/server/index.js";
 import {ServerApi} from "../../interfaces.js";
 
-export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<Api, ReqTypes> {
+export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<ServerApi<Api>, ReqTypes> {
   // All routes return JSON, use a server auto-generator
   return getGenericJsonServer<ServerApi<Api>, ReqTypes>({routesData, getReturnTypes, getReqSerializers}, config, api);
 }
diff --git a/packages/api/src/beacon/server/lodestar.ts b/packages/api/src/beacon/server/lodestar.ts
index b52ed9832f69..5c61b93e0798 100644
--- a/packages/api/src/beacon/server/lodestar.ts
+++ b/packages/api/src/beacon/server/lodestar.ts
@@ -3,7 +3,7 @@ import {Api, ReqTypes, routesData, getReturnTypes, getReqSerializers} from "../r
 import {ServerRoutes, getGenericJsonServer} from "../../utils/server/index.js";
 import {ServerApi} from "../../interfaces.js";
 
-export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<Api, ReqTypes> {
+export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<ServerApi<Api>, ReqTypes> {
   // All routes return JSON, use a server auto-generator
   return getGenericJsonServer<ServerApi<Api>, ReqTypes>({routesData, getReturnTypes, getReqSerializers}, config, api);
 }
diff --git a/packages/api/src/beacon/server/proof.ts b/packages/api/src/beacon/server/proof.ts
index a03ae472bf78..325da95afa5d 100644
--- a/packages/api/src/beacon/server/proof.ts
+++ b/packages/api/src/beacon/server/proof.ts
@@ -18,7 +18,8 @@ export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerR
       ...serverRoutes.getStateProof,
       handler: async (req) => {
         const args = reqSerializers.getStateProof.parseReq(req);
-        const {data} = await api.getStateProof(...args);
+        const apiRes = await api.getStateProof(...args);
+        const data = "status" in apiRes ? apiRes.response?.data : apiRes.data;
         const leaves = (data as CompactMultiProof).leaves;
         const response = new Uint8Array(32 * leaves.length);
         for (let i = 0; i < leaves.length; i++) {
@@ -32,7 +33,8 @@ export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerR
       ...serverRoutes.getBlockProof,
       handler: async (req) => {
         const args = reqSerializers.getBlockProof.parseReq(req);
-        const {data} = await api.getBlockProof(...args);
+        const apiRes = await api.getBlockProof(...args);
+        const data = "status" in apiRes ? apiRes.response?.data : apiRes.data;
         const leaves = (data as CompactMultiProof).leaves;
         const response = new Uint8Array(32 * leaves.length);
         for (let i = 0; i < leaves.length; i++) {
diff --git a/packages/api/src/beacon/server/validator.ts b/packages/api/src/beacon/server/validator.ts
index 6bf446e05a16..f128557d2820 100644
--- a/packages/api/src/beacon/server/validator.ts
+++ b/packages/api/src/beacon/server/validator.ts
@@ -3,7 +3,7 @@ import {Api, ReqTypes, routesData, getReturnTypes, getReqSerializers} from "../r
 import {ServerRoutes, getGenericJsonServer} from "../../utils/server/index.js";
 import {ServerApi} from "../../interfaces.js";
 
-export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<Api, ReqTypes> {
+export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<ServerApi<Api>, ReqTypes> {
   // All routes return JSON, use a server auto-generator
   return getGenericJsonServer<ServerApi<Api>, ReqTypes>({routesData, getReturnTypes, getReqSerializers}, config, api);
 }
diff --git a/packages/api/src/builder/server/index.ts b/packages/api/src/builder/server/index.ts
index 2421abbc0dcc..902004b9daef 100644
--- a/packages/api/src/builder/server/index.ts
+++ b/packages/api/src/builder/server/index.ts
@@ -12,7 +12,7 @@ import {Api, ReqTypes, routesData, getReturnTypes, getReqSerializers} from "../r
 // Re-export for convenience
 export {RouteConfig};
 
-export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<Api, ReqTypes> {
+export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<ServerApi<Api>, ReqTypes> {
   // All routes return JSON, use a server auto-generator
   return getGenericJsonServer<ServerApi<Api>, ReqTypes>({routesData, getReturnTypes, getReqSerializers}, config, api);
 }
diff --git a/packages/api/src/interfaces.ts b/packages/api/src/interfaces.ts
index a5f245de9131..9a441148fe03 100644
--- a/packages/api/src/interfaces.ts
+++ b/packages/api/src/interfaces.ts
@@ -4,8 +4,7 @@ import {Resolves} from "./utils/types.js";
 /* eslint-disable @typescript-eslint/no-explicit-any */
 
 export type APIClientHandler = (...args: any) => PromiseLike<ApiClientResponse>;
-export type APIServerHandler = (...args: any) => PromiseLike<unknown>;
-
+export type APIServerHandler = (...args: any) => PromiseLike<ApiServerResponse<ApiClientResponse>>;
 export type ApiClientSuccessResponse<S extends keyof any, T> = {ok: true; status: S; response: T; error?: never};
 export type ApiClientErrorResponse<S extends Exclude<HttpStatusCode, HttpSuccessCodes>> = {
   ok: false;
@@ -21,17 +20,36 @@ export type ApiClientResponse<
   | {[K in E]: ApiClientErrorResponse<K>}[E]
   | ApiClientErrorResponse<HttpStatusCode.INTERNAL_SERVER_ERROR>;
 
-export type ApiClientResponseData<T extends ApiClientResponse> = T extends {ok: true; response: infer R} ? R : never;
+export type ApiServerResponse<T extends ApiClientResponse> = T extends {
+  ok: true;
+  response: infer R;
+  status: infer S;
+}
+  ? R | {status: S; response: R}
+  : never;
+
+export type ApiClientResolvesData<T extends ApiClientResponse> = T extends {ok: true; response: infer R} ? R : never;
+export type ApiServerResolvesData<T extends ApiServerResponse<ApiClientResponse>> = T extends void
+  ? never
+  : T extends {
+      status: number;
+      response: infer R;
+    }
+  ? R
+  : never;
 
 export type GenericRequestObject = Record<string, unknown>;
-export type GenericResponseObject = {code: (code: number) => void};
 
 export type ServerApi<T extends Record<string, APIClientHandler>> = {
   [K in keyof T]: (
-    ...args: [...args: Parameters<T[K]>, req?: GenericRequestObject, res?: GenericResponseObject]
-  ) => Promise<ApiClientResponseData<Resolves<T[K]>>>;
+    ...args: [...args: Parameters<T[K]>, req?: GenericRequestObject]
+  ) => Promise<ApiServerResponse<Resolves<T[K]>>>;
 };
 
 export type ClientApi<T extends Record<string, APIServerHandler>> = {
-  [K in keyof T]: (...args: Parameters<T[K]>) => Promise<ApiClientResponse<{[HttpStatusCode.OK]: Resolves<T[K]>}>>;
+  [K in keyof T]: ApiServerResolvesData<Resolves<T[K]>> extends void
+    ? never
+    : (...args: Parameters<T[K]>) => Promise<ApiClientResponse<{[HttpStatusCode.OK]: Resolves<T[K]>}>>;
 };
+
+type T = ApiServerResponse<ApiClientResponse<{[HttpStatusCode.OK]: boolean}>>;
diff --git a/packages/api/src/keymanager/server/index.ts b/packages/api/src/keymanager/server/index.ts
index 2421abbc0dcc..902004b9daef 100644
--- a/packages/api/src/keymanager/server/index.ts
+++ b/packages/api/src/keymanager/server/index.ts
@@ -12,7 +12,7 @@ import {Api, ReqTypes, routesData, getReturnTypes, getReqSerializers} from "../r
 // Re-export for convenience
 export {RouteConfig};
 
-export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<Api, ReqTypes> {
+export function getRoutes(config: ChainForkConfig, api: ServerApi<Api>): ServerRoutes<ServerApi<Api>, ReqTypes> {
   // All routes return JSON, use a server auto-generator
   return getGenericJsonServer<ServerApi<Api>, ReqTypes>({routesData, getReturnTypes, getReqSerializers}, config, api);
 }
diff --git a/packages/api/src/utils/server/genericJsonServer.ts b/packages/api/src/utils/server/genericJsonServer.ts
index a27f1ea69723..e7753a25fedf 100644
--- a/packages/api/src/utils/server/genericJsonServer.ts
+++ b/packages/api/src/utils/server/genericJsonServer.ts
@@ -1,10 +1,11 @@
 import type {FastifyInstance} from "fastify";
 import {mapValues} from "@lodestar/utils";
 import {ChainForkConfig} from "@lodestar/config";
-import {ReqGeneric, TypeJson, Resolves, RouteGroupDefinition} from "../types.js";
+import {ReqGeneric, TypeJson, RouteGroupDefinition} from "../types.js";
 import {getFastifySchema} from "../schema.js";
 import {toColonNotationPath} from "../urlFormat.js";
 import {APIServerHandler} from "../../interfaces.js";
+import {HttpStatusCode} from "../client/httpStatusCode.js";
 import {ServerRoute} from "./types.js";
 
 // See /packages/api/src/routes/index.ts for reasoning
@@ -42,14 +43,27 @@ export function getGenericJsonServer<
 
       handler: async function handler(this: FastifyInstance, req, resp): Promise<unknown | void> {
         const args: any[] = routeSerdes.parseReq(req as ReqGeneric as ReqTypes[keyof Api]);
-        const data = (await api[routeId](...args, req, resp)) as Resolves<Api[keyof Api]>;
 
-        if (routeDef.statusOk !== undefined) {
-          resp.statusCode = routeDef.statusOk;
-        }
+        // The type resolves here is `unknown | void | {status: number; response: unknown | void}`
+        // which end up being just `unknown` in the end because of the `unknown | void` part
+        const data = await api[routeId](...args, req, resp);
+
+        const status =
+          "status" in (data as {status: number; response: unknown})
+            ? (data as {status: number; response: unknown}).status
+            : routeDef.statusOk !== undefined
+            ? routeDef.statusOk
+            : HttpStatusCode.OK;
+
+        const response =
+          "status" in (data as {status: number; response: unknown})
+            ? (data as {status: number; response: unknown}).response
+            : data;
+
+        resp.statusCode = status;
 
         if (returnType) {
-          return returnType.toJson(data);
+          return returnType.toJson(response);
         } else {
           return {};
         }
diff --git a/packages/api/src/utils/types.ts b/packages/api/src/utils/types.ts
index a62fb30b7270..9da861fab266 100644
--- a/packages/api/src/utils/types.ts
+++ b/packages/api/src/utils/types.ts
@@ -2,7 +2,8 @@ import {isBasicType, ListBasicType, Type, isCompositeType, ListCompositeType, Ar
 import {ForkName} from "@lodestar/params";
 import {ChainForkConfig} from "@lodestar/config";
 import {objectToExpectedCase} from "@lodestar/utils";
-import {APIClientHandler, ApiClientResponseData, APIServerHandler, ClientApi} from "../interfaces.js";
+import {APIClientHandler, ApiClientResolvesData, ApiServerResponse} from "../interfaces.js";
+import {APIServerHandler, ClientApi} from "../interfaces.js";
 import {Schema, SchemaDefinition} from "./schema.js";
 
 // See /packages/api/src/routes/index.ts for reasoning
@@ -219,11 +220,11 @@ export function sameType<T>(): TypeJson<T> {
 // RETURN
 //
 export type KeysOfNonVoidResolveValues<Api extends Record<string, APIClientHandler>> = {
-  [K in keyof Api]: ApiClientResponseData<Resolves<Api[K]>> extends void ? never : K;
+  [K in keyof Api]: ApiClientResolvesData<Resolves<Api[K]>> extends void ? never : K;
 }[keyof Api];
 
 export type ReturnTypes<Api extends Record<string, APIClientHandler>> = {
-  [K in keyof Pick<Api, KeysOfNonVoidResolveValues<Api>>]: TypeJson<ApiClientResponseData<Resolves<Api[K]>>>;
+  [K in keyof Pick<Api, KeysOfNonVoidResolveValues<Api>>]: TypeJson<ApiServerResponse<Resolves<Api[K]>>>;
 };
 
 export type RoutesData<Api extends Record<string, APIServerHandler>> = {[K in keyof Api]: RouteDef};
diff --git a/packages/api/test/utils/genericServerTest.ts b/packages/api/test/utils/genericServerTest.ts
index 9f6dd45da2c8..7f13d959f1b3 100644
--- a/packages/api/test/utils/genericServerTest.ts
+++ b/packages/api/test/utils/genericServerTest.ts
@@ -7,23 +7,20 @@ import {FetchOpts, HttpClient, IHttpClient} from "../../src/utils/client/index.j
 import {ServerRoutes} from "../../src/utils/server/genericJsonServer.js";
 import {registerRoute} from "../../src/utils/server/registerRoute.js";
 import {HttpStatusCode} from "../../src/utils/client/httpStatusCode.js";
-import {APIClientHandler, ApiClientResponseData, ServerApi} from "../../src/interfaces.js";
+import {APIClientHandler, ApiServerResponse, ServerApi} from "../../src/interfaces.js";
 import {getMockApi, getTestServer} from "./utils.js";
 
 type IgnoreVoid<T> = T extends void ? undefined : T;
 
-export type GenericServerTestCases<Api extends Record<string, APIClientHandler>> = {
+export type GenericServerTestCases<Api extends ClientApi> = {
   [K in keyof Api]: {
     args: Parameters<Api[K]>;
-    res: IgnoreVoid<ApiClientResponseData<Resolves<Api[K]>>>;
+    res: IgnoreVoid<ApiServerResponse<Resolves<Api[K]>>>;
     query?: FetchOpts["query"];
   };
 };
 
-export function runGenericServerTest<
-  Api extends Record<string, APIClientHandler>,
-  ReqTypes extends {[K in keyof Api]: ReqGeneric},
->(
+export function runGenericServerTest<Api extends ClientApi, ReqTypes extends {[K in keyof Api]: ReqGeneric}>(
   config: ChainForkConfig,
   getClient: (config: ChainForkConfig, https: IHttpClient) => Api,
   getRoutes: (config: ChainForkConfig, api: ServerApi<Api>) => ServerRoutes<ServerApi<Api>, ReqTypes>,
diff --git a/packages/beacon-node/src/api/impl/node/index.ts b/packages/beacon-node/src/api/impl/node/index.ts
index 902fa6fd6275..1087594ce94f 100644
--- a/packages/beacon-node/src/api/impl/node/index.ts
+++ b/packages/beacon-node/src/api/impl/node/index.ts
@@ -66,7 +66,7 @@ export function getNodeApi(
       return {data: sync.getSyncStatus()};
     },
 
-    async getHealth(options, _req, res) {
+    async getHealth(options) {
       // Custom value passed via `syncing_status` query parameter
       const syncingStatus = options?.syncingStatus;
 
@@ -77,10 +77,10 @@ export function getNodeApi(
 
       if (sync.getSyncStatus().isSyncing) {
         // 206: Node is syncing but can serve incomplete data
-        res?.code(syncingStatus ?? routes.node.NodeHealth.SYNCING);
+        return {status: syncingStatus ?? routes.node.NodeHealth.SYNCING, response: undefined};
       } else {
         // 200: Node is ready
-        res?.code(routes.node.NodeHealth.READY);
+        return {status: routes.node.NodeHealth.READY, response: undefined};
       }
       // else {
       //   503: Node not initialized or having issues
diff --git a/packages/beacon-node/src/api/impl/validator/index.ts b/packages/beacon-node/src/api/impl/validator/index.ts
index bc0b25a953d6..c7c9fd939c57 100644
--- a/packages/beacon-node/src/api/impl/validator/index.ts
+++ b/packages/beacon-node/src/api/impl/validator/index.ts
@@ -287,7 +287,9 @@ export function getValidatorApi({
     randaoReveal,
     graffiti
   ) {
-    const {data, version, blockValue} = await produceBlockV2(slot, randaoReveal, graffiti);
+    const produceBlockV2Resp = await produceBlockV2(slot, randaoReveal, graffiti);
+    const {data, version, blockValue} =
+      "status" in produceBlockV2Resp ? produceBlockV2Resp.response : produceBlockV2Resp;
     if ((data as BlockContents).block !== undefined) {
       throw Error(`Invalid block contents for produceBlock at fork=${version}`);
     } else {