# MicroservicesModule

**Kind:** Class

**Source:** [`packages/microservices/microservices-module.ts`](https://github.com/nestjs/nest/blob/master/packages/microservices/microservices-module.ts#L23)

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

`MicroservicesModule` coordinates microservice transport setup within the application. It registers configured listeners and clients, binds them during startup, and closes active connections during shutdown.

## Methods

| Method | Signature | Returns |
|---|---|---|
| `register` | `register(container: NestContainer, graphInspector: GraphInspector, config: ApplicationConfig, options: TAppOptions)` | `void` |
| `setupListeners` | `setupListeners(container: NestContainer, serverInstance: Server)` | `void` |
| `setupClients` | `setupClients(container: NestContainer)` | `void` |
| `bindListeners` | `bindListeners(controllers: Map<string | symbol | Function, InstanceWrapper<Controller>>, serverInstance: Server, moduleName: string)` | `void` |
| `bindClients` | `bindClients(items: Map<string | symbol | Function, InstanceWrapper<unknown>>)` | `void` |
| `close` | `close()` | `void` |

## Where it refuses work

- `MicroservicesModule` stops the work with `RuntimeException` when `!this.listenersController`, in 2 places.
- `MicroservicesModule` stops the work with an early return when `this.appOptions?.preview`.

## Diagram

```mermaid
graph LR
  A[Application Bootstrap] --> B[MicroservicesModule]
  B --> C[register()]
  C --> D[setupListeners()]
  C --> E[setupClients()]
  D --> F[bindListeners()]
  E --> G[bindClients()]
  F --> H[Incoming Microservice Messages]
  G --> I[Outbound Client Requests]
  B --> J[close()]
  J --> K[Close Listeners and Clients]
```

## Usage

```ts
import { MicroservicesModule } from '@your-scope/microservices';

// Create the module with the application's configured microservice
// listeners and client connections.
const microservices = new MicroservicesModule(/* application dependencies */);

// During application startup, register and bind transports.
await microservices.register();

// The application can now receive messages through listeners
// and send requests through configured clients.

// During graceful shutdown, release transport resources.
await microservices.close();
```

## AI Coding Instructions

- Keep listener and client initialization separated: use `setupListeners()` and `setupClients()` for construction, then `bindListeners()` and `bindClients()` for activation.
- Ensure `register()` is called during application bootstrap before handling microservice traffic.
- Add new transport integrations through the module’s setup and binding flow rather than creating untracked connections elsewhere.
- Always invoke `close()` during graceful shutdown to release listeners, client connections, and related resources.
- Preserve startup ordering so listeners and clients are fully configured before they are bound.

## Relationships

- IMPORTS → `Controller`
- IMPORTS → `NestApplicationContextOptions`
- IMPORTS → `ApplicationConfig`
- IMPORTS → `RuntimeException`
- IMPORTS → `GuardsConsumer`
- IMPORTS → `GuardsContextCreator`
- IMPORTS → `NestContainer`
- IMPORTS → `Injector`
- IMPORTS → `InstanceWrapper`
- IMPORTS → `GraphInspector`
- IMPORTS → `InterceptorsConsumer`
- IMPORTS → `InterceptorsContextCreator`
- IMPORTS → `PipesConsumer`
- IMPORTS → `PipesContextCreator`

## Used by

1 reference from 1 file. Each is a place in this repository where the symbol is actually used — go read one rather than trusting an example.

### Imported by (1)

- `NestApplication` — `packages/core/nest-application.ts`:54