# Route Middleware

In addition to global middleware, you can define middleware that only applies to a specific subdirectory of your application.

## Usage

Place a `middleware.ts` file inside a route directory.

```
src/routes/
  app/
    middleware.ts    <-- Runs for all /app/* routes
    dashboard.tsx
    settings.tsx
```

## Execution Order

Middleware runs in a top-down order:

1.  Global `src/middleware.ts`
2.  Route `src/routes/app/middleware.ts`
3.  Nested `src/routes/app/admin/middleware.ts`
4.  Route Loader/Action

## Common Use Cases

-   **Authentication**: Checking if a user is logged in before accessing `/app`.
-   **Logging**: Tracking requests to specific API endpoints.
-   **Headers**: Adding CORS headers to API routes.