Authentication in Next.js 15: The Pattern I Use for Every SaaS

A developer outlines a custom JWT auth pattern for Next.js 15 SaaS apps instead of using NextAuth by default.

The flow verifies passwords, signs session payloads, and stores the token in an httpOnly cookie.

Login happens through a server action, keeping auth logic on the server side.

Middleware protects private routes and redirects signed-in users away from auth pages.

The approach offers a simpler, more controlled setup for route protection and session handling.