What is the Nest request lifecycle?
Try code in the playgroundUnderstand the concept
The request lifecycle is the order in which Nest processes an incoming request and produces a response. Different extension points handle different concerns, such as access checks, input conversion and response wrapping. Knowing the order helps explain why code in one stage cannot rely on work that happens later.
Important ideas
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Middleware → guards → interceptors before → pipes → controller/service.
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The response returns through interceptors in reverse order.
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Exception filters handle uncaught errors; they are not a normal success step.
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A guard runs before pipes, so it should not assume route arguments already passed DTO validation.
Can you explain it without the notes?
What is the Nest request lifecycle?
Use your own words. Explain an example and one limitation before checking the explanation.
Check your explanation
The request lifecycle is the order in which Nest processes an incoming request and produces a response. Different extension points handle different concerns, such as access checks, input conversion and response wrapping. Knowing the order helps explain why code in one stage cannot rely on work that happens later.
Turn this concept into a clear answer.
- Show both inbound and outbound paths; exception filters are used when an uncaught error reaches the exception layer.
Keep connecting the ideas.
Next lesson: How do global, controller and route handlers interact?Adapted from 03_NESTJS.md · “What is the Nest request lifecycle?”. Examples are study fragments; framework behavior can depend on your version.