Authentication Part 2 with NestJS

This post continues the fast NestJS authentication flow. It is based on my original Medium article, Authentication part 2 using NestJS.

The goal is to create the basic auth and users modules before adding a real database in the next step.

Modules

Start with two modules:

• AuthModule
• UsersModule

The users module owns basic user lookup and creation behavior. The auth module owns sign-in, sign-up, JWT generation, and route protection.

Auth service

The auth service depends on the users service and the NestJS JWT service.

For sign-in, it validates credentials, builds a payload, and returns an access token.

For sign-up, it delegates user creation and removes sensitive fields from the response.

Auth guard

The protected profile route uses a guard to validate the incoming JWT. The guard extracts the token, verifies it, and attaches the user payload to the request.

That gives the controller access to authenticated user data.

Controller

The controller exposes a small API:

• sign up
• sign in
• profile

At this stage, the project keeps persistence simple. The next step is adding Postgres and TypeORM so users survive application restarts.

Takeaways

This part creates the shape of the auth flow: modules, services, JWTs, and guards. It is intentionally small so the structure is clear before adding database complexity.