nestjs/nest · error · Error

Not initialized. Please call the "listen"/"startAllMicroserv

Error message

Not initialized. Please call the "listen"/"startAllMicroservices" method before accessing the server.

What it means

Error "Not initialized. Please call the "listen"/"startAllMicroservices" method before accessing the server." thrown in nestjs/nest.

Source

Thrown at packages/microservices/server/server-rmq.ts:383

    correlationId: string,
    context: RmqContext,
  ): void {
    const outgoingResponse = this.serializer.serialize(
      message as unknown as OutgoingResponse,
    );
    const options = outgoingResponse.options;
    delete outgoingResponse.options;

    const buffer = Buffer.from(JSON.stringify(outgoingResponse));
    const sendOptions = { correlationId, ...options };

    this.onProcessingEndHook?.(this.transportId, context);
    this.channel!.sendToQueue(replyTo, buffer, sendOptions);
  }

  public unwrap<T>(): T {
    if (!this.server) {
      throw new Error(
        'Not initialized. Please call the "listen"/"startAllMicroservices" method before accessing the server.',
      );
    }
    return this.server as T;
  }

  public on<
    EventKey extends keyof RmqEvents = keyof RmqEvents,
    EventCallback extends RmqEvents[EventKey] = RmqEvents[EventKey],
  >(event: EventKey, callback: EventCallback) {
    if (this.server) {
      this.server.addListener(event, callback);
    } else {
      this.pendingEventListeners.push({ event, callback });
    }
  }

  public getHandlerByPattern(pattern: string): MessageHandler | null {

View on GitHub (pinned to 6ec0e2783d)

Solutions

1. Call app.listen() or app.startAllMicroservices() before accessing the RMQ server instance.
2. Await listen() so the RabbitMQ channel/connection is set up before use.

Example fix

const app = await NestFactory.createMicroservice(AppModule, opts);
await app.listen();
const server = app.get(ServerRMQ);

When it happens

Trigger: Thrown at packages/microservices/server/server-rmq.ts:383 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of nestjs/nest@6ec0e2783d (2026-08-03). Data as JSON: /data/errors/dca14831dbe43314.json. Report an issue: GitHub.