How to build a register user flow in Next.js 15 (frontend, backend, database, email)

A Next.js 15 tutorial shows how to build a full user registration flow, from a signup form to a backend register endpoint.

It uses Postgres tables for users and email verification tokens, with citext support for safer email handling.

A verification email sent through Resend activates the account before any session cookie is issued.

The approach helps block abuse by requiring email verification before sign-in, while also outlining a secure auth database design.