Nest applications handle requests and produce responses in a sequence we refer to as the request lifecycle. With the use of middleware, pipes, guards, and interceptors, it can be challenging to track down where a particular piece of code executes during the request lifecycle, especially as global, controller level, and route level components come into play. In general, a request flows through middleware to guards, then to interceptors, then to pipes and finally back to interceptors on the return path (as the response is generated).

Request lifecycle

1. Middleware
2. Guards
3. Pre Interceptors
4. Pipes
5. Controller
6. Service
7. Post Interceptors
8. Filters

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