Build your own password authentication

Build a password authentication system with Postgres, bcrypt and the blowfish algorithm. No auth provider and no external service.

We start with a reactive login form, add a database migration for the users table, then hash and check passwords by hand in Postgres to see how it works. Then we wire it together end to end: the form, the rpc behind it, and the session.

We finish by having Claude Code build the whole thing from scratch: a fully functioning authentication system with beautiful sign in and create account pages, and the tests to prove it works.