Stack Auth

Open-source authentication platform for Next.js and React, built as an alternative to Auth0 and Clerk.

Open source alternative to:

Stack Auth is an open-source, self-hostable authentication and user management solution designed specifically for modern web apps built with Next.js and React. It is a developer-friendly alternative to Auth0 and Clerk, offering pre-built UI components, server and client SDKs, and a hosted dashboard.

It supports email/password login, magic links, OAuth social providers (Google, GitHub, Facebook, and more), session management, multi-tenant organizations, and role-based access control — all configurable with minimal code. Stack Auth ships with fully functional sign-in, sign-up, and account pages that you can drop into your Next.js app in minutes.

As an open-source project it can be self-hosted on your own infrastructure, giving you full control over user data. It is also available as a managed cloud service for teams that prefer a hosted option.