# RmqOptions

**Kind:** Interface

**Source:** [`packages/microservices/interfaces/microservice-configuration.interface.ts`](https://github.com/nestjs/nest/blob/master/packages/microservices/interfaces/microservice-configuration.interface.ts#L222)

**Part of:** [Microservices](subsystem-packages-microservices)

`RmqOptions` configures a NestJS microservice that uses the RabbitMQ (`Transport.RMQ`) transport. It defines connection URLs, queue and exchange behavior, consumer acknowledgement settings, message serialization, routing, and connection retry behavior.

## Properties

| Property | Type |
|---|---|
| `transport` | `Transport.RMQ` |
| `options` | `{ urls?: string[] | RmqUrl[]; queue?: string; prefetchCount?: number; isGlobalPrefetchCount?: boolean; queueOptions?: AmqplibQueueOptions; socketOptions?: AmqpConnectionManagerSocketOptions; noAck?: boolean; consumerTag?: string; serializer?: Serializer; deserializer?: Deserializer; replyQueue?: string; persistent?: boolean; headers?: Record<string, string>; noAssert?: boolean; exchange?: string; exchangeType?: 'direct' | 'fanout' | 'topic' | 'headers' | (string & {}); exchangeArguments?: Record<string, string>; routingKey?: string; wildcards?: boolean; maxConnectionAttempts?: number; }` |

## Diagram

```mermaid
graph LR
  App[NestJS Application] --> Config[RmqOptions]
  Config --> Transport[Transport.RMQ]
  Config --> Connection[AMQP Connection URLs]
  Config --> Queue[Queue Configuration]
  Config --> Exchange[Exchange and Routing]
  Config --> Consumer[Consumer Settings]
  Config --> Serialization[Serializer / Deserializer]

  Connection --> RabbitMQ[RabbitMQ Broker]
  Queue --> RabbitMQ
  Exchange --> RabbitMQ
  Consumer --> RabbitMQ
```

## Usage

```ts
import { NestFactory } from '@nestjs/core';
import { Transport, RmqOptions } from '@nestjs/microservices';
import { AppModule } from './app.module';

async function bootstrap() {
  const rmqOptions: RmqOptions = {
    transport: Transport.RMQ,
    options: {
      urls: ['amqp://guest:guest@localhost:5672'],
      queue: 'orders',
      queueOptions: {
        durable: true,
      },
      prefetchCount: 10,
      noAck: false,
      persistent: true,
      exchange: 'events',
      exchangeType: 'topic',
      routingKey: 'orders.created',
      maxConnectionAttempts: 5,
    },
  };

  const app = await NestFactory.createMicroservice(AppModule, rmqOptions);
  await app.listen();
}

bootstrap();
```

## AI Coding Instructions

- Always set `transport: Transport.RMQ`; this interface is specifically for RabbitMQ microservice configuration.
- Configure a durable `queue` and `queueOptions.durable: true` when messages must survive broker restarts.
- Set `noAck: false` for reliable processing, then explicitly acknowledge messages in handlers after successful work.
- Use `exchange`, `exchangeType`, and `routingKey` together when implementing publish/subscribe or topic-based routing.
- Provide custom `serializer` and `deserializer` only when all producers and consumers agree on the message format.