Using NestJS Pipes, Guards, Interceptors

When to use

• Implementing authentication/authorization
• Adding logging, caching, response shaping
• Cross-cutting concerns that shouldn't live in controllers

Core rules

1. Pipes: transform/validate input (use ValidationPipe globally)
2. Guards: authenticate/authorize requests (AuthGuard, RolesGuard)
3. Interceptors: transform responses, log, cache, timeout (ClassSerializerInterceptor)
4. Implement as @Injectable() classes, register globally or at controller/route level
5. No logic in controllers that belongs in these cross-cutting components

Reference shape (TypeScript)