Authentication becomes more real once users are stored in a database. This post is based on my original Medium article, Authentication part 3 using NestJS and Postgres database neon.tech.
It continues a simple NestJS auth flow by adding TypeORM, Postgres, password hashing, and database migrations.
Local Postgres
The local database runs through Docker Compose. That gives the project a repeatable Postgres instance with known credentials and a known port.
Once Postgres is running, NestJS can connect through TypeOrmModule.
User entity
The user table starts with:
idusernamepassword
The password should never be stored as plain text. TypeORM's BeforeInsert hook can hash the password before saving the entity.
User service
The user service uses a TypeORM repository to:
- find a user by username
- create a user
- reject duplicate usernames
- validate credentials
- compare hashed passwords
That gives the auth service a clean dependency.
Auth service and controller
The auth service signs in users by validating credentials and issuing a JWT. It signs up users by creating the account and removing the password from the response.
The controller exposes:
POST /auth/signUpPOST /auth/signIn- protected
GET /auth/profile
Neon
Neon can host the production Postgres database. The main difference is configuration: production database credentials should come from environment variables instead of local Docker values.
Takeaways
This step turns the in-memory auth example into a database-backed flow. It is still simple, but it includes the core pieces: persistence, hashing, migrations, and deployment-ready configuration.