> For the complete documentation index, see [llms.txt](https://docs.nestjstools.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nestjstools.com/best-practice/consumer-as-the-background-process.md).

# Consumer as the background process

> ⚠️ **Before You Continue**
>
> It's recommended to read the [Bootstrap ](/best-practice/bootstrap-http-worker-mode.md)Guide first.\
> It provides a higher-level, smarter approach for managing messaging in both HTTP server and worker (microservice) modes.
>
> This page is useful if you're configuring consumers manually or outside the bootstrap utility.

### 🧾 Consumer as a Background Process

In your messaging configuration, you have the ability to run certain channels in **background consumer mode**, meaning the application will continuously poll and process messages from a queue (e.g., RabbitMQ).

This behavior is **explicitly controlled** using the `enableConsumer` flag inside the channel configuration.

***

#### ✅ Enabling or Disabling Consumers

Each channel can individually opt into message consumption:

```ts
new AmqpChannelConfig({
  name: 'amqp-command.channel',
  connectionUri: 'amqp://guest:guest@localhost:5672/',
  exchangeName: 'book_shop.exchange',
  bindingKeys: ['book_shop.#'],
  exchangeType: ExchangeType.TOPIC,
  queue: 'book_shop.command',
  enableConsumer: process.env.CONSUMER_ENABLED === 'true' ?? false, // ← starts the background consumer
})
```

Setting `enableConsumer: true` allows the messaging module to **automatically listen to that queue** and handle incoming messages to the proper handlers in your NestJS app.

***

### ⚙️ Running the Consumer as a Dedicated Microservice

In addition to toggling `enableConsumer` in your channel config, you can fully isolate message consumption into its own process using **NestJS microservice mode**.

This is useful when you want to **separate HTTP requests from background processing**, scale them independently, or run consumers in isolated environments (e.g., workers).

***

#### 🔁 From HTTP App to Microservice Consumer

Your standard `main.ts` for a typical HTTP NestJS app might look like this:

```ts
// Standard HTTP entry point
process.env.CONSUMER_ENABLED = 'false';
import { NestFactory } from '@nestjs/core';
import { BookModule } from './book.module';

async function bootstrap() {
  const app = await NestFactory.create(BookModule.forRoot());
  await app.listen(process.env.port ?? 3000);
}
bootstrap();
```

You can **create** `worker.ts` **a microservice-based consumer** by doing the following:

#### ✅ Microservice Consumer Entry

```ts
// microservice-main.ts
process.env.CONSUMER_ENABLED = 'true'; // ensures consumers are enabled via config

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

async function bootstrap() {
  const app = await NestFactory.createMicroservice<MicroserviceOptions>(
    AppModule,
    {
      transport: Transport.TCP,
    },
  );
  await app.listen();
}
bootstrap();
```


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