# MiddlewareConsumer

**Kind:** Interface

**Source:** [`packages/common/interfaces/middleware/middleware-consumer.interface.ts`](https://github.com/nestjs/nest/blob/master/packages/common/interfaces/middleware/middleware-consumer.interface.ts#L11)

**Part of:** [Common](subsystem-packages-common)

Interface defining method for applying user defined middleware to routes.

`MiddlewareConsumer` defines the API used to register application middleware during module configuration. Its `apply()` method accepts one or more middleware classes or functions and returns a configuration proxy that can target specific routes, controllers, HTTP methods, or exclusions.

## Diagram

```mermaid
graph LR
  A[Module.configure] --> B[MiddlewareConsumer]
  B --> C[apply Middleware]
  C --> D[MiddlewareConfigProxy]
  D --> E[forRoutes / exclude]
  E --> F[Matched HTTP Routes]
  F --> G[Middleware Execution]
  G --> H[Route Handler]
```

## Usage

```ts
import { MiddlewareConsumer, Module, NestModule, RequestMethod } from '@nestjs/common';
import { LoggerMiddleware } from './logger.middleware';
import { CatsController } from './cats.controller';

@Module({
  controllers: [CatsController],
})
export class CatsModule implements NestModule {
  configure(consumer: MiddlewareConsumer) {
    consumer
      .apply(LoggerMiddleware)
      .exclude({ path: 'cats/health', method: RequestMethod.GET })
      .forRoutes(CatsController);
  }
}
```

## AI Coding Instructions

- Use `MiddlewareConsumer` inside a module's `configure()` method, typically by implementing `NestModule`.
- Pass middleware classes or compatible middleware functions to `consumer.apply()`.
- Chain `forRoutes()` after `apply()` to ensure middleware is attached to intended controllers or route patterns.
- Use `exclude()` before `forRoutes()` when a middleware should not run for selected endpoints.
- Keep middleware registration module-specific when possible; use global middleware only when it truly applies across the application.

## Used by

4 references from 4 files. Each is a place in this repository where the symbol is actually used — go read one rather than trusting an example.

### Imported by (4)

- `CoreModule` — `integration/inspector/src/core/core.module.ts`:8
- `AppModule` — `integration/nest-application/global-prefix/src/app.module.ts`:7
- `AppModule` — `integration/versioning/src/app.module.ts`:13
- `MiddlewareBuilder` — `packages/core/middleware/builder.ts`:17