Guard binding levels in NestJS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a guard in NestJS?

A guard is a special class that controls whether a request can proceed to the route handler. It acts like a security checkpoint to allow or block access.

beginner

Name the three main levels where guards can be bound in NestJS.

Guards can be bound at the method level, controller level, and global level.

intermediate

How does a guard bound at the global level behave?

A global guard runs for every incoming request in the application, no matter which controller or method is called.

intermediate

If a guard is applied at both controller and method levels, which one runs first?

The guard at the global level runs first, then the guard at the controller level runs, and finally the guard at the method level runs.

beginner

Why would you use method-level guard binding instead of global or controller level?

Method-level guards are used when you want to protect or restrict access to a specific route only, giving fine-grained control.

Which guard binding level applies to all routes in a NestJS app?

A Global level

B Controller level

C Method level

D Module level

Global guards run for every request in the app, regardless of controller or method.

When multiple guards are applied, which order do they run in NestJS?

A Global, Controller, Method

B Method, Controller, Global

C Controller, Global, Method

D Method, Global, Controller

Guards run from the broadest scope (global) to the narrowest (method).

Where do you bind a guard to protect only one specific route?

A Global level

B Controller level

C Method level

D App module

Method-level guards protect individual routes.

What happens if a global guard denies access?

A Controller guards still run

B Request proceeds anyway

C Method guards override it

D Request is blocked immediately

If a global guard denies access, the request stops and does not proceed.

Can you apply multiple guards at the same binding level?

A Yes, but only the first runs

B Yes, they run in the order declared

C No, only one guard per level

D No, guards must be global

Multiple guards can be applied and run in the order they are declared.

Explain the three guard binding levels in NestJS and when you might use each.

Think about how wide or narrow the guard's effect is.

Describe the order in which guards run when applied at multiple levels and why this order matters.

Consider a security checkpoint analogy with layers.