Stack Auth (YC S24)

Stack Auth, a Y Combinator S24-backed project, is an open-source and self-hostable user authentication and authorization platform designed for developers. It offers a developer-friendly interface with components like <SignIn /> and <AccountSettings />, allowing quick setup within 5 minutes. The platform integrates seamlessly with Next.js and provides beautifully styled components for easy implementation.

Stack Auth manages JWTs and access tokens, simplifying performance optimization without requiring developers to handle token management directly. It supports comprehensive authentication features, including passwords, SSO, and 2FA, and offers flexible authorization capabilities with permission trees and role-based access control (RBAC). The platform also facilitates B2B customer management through organizations and teams, and integrates third-party OAuth APIs effortlessly.

User management is streamlined with REST APIs, webhooks for service synchronization, and user impersonation for debugging. Stack Auth stands out among competitors like Auth0 and Supabase Auth by being entirely open-source, cost-effective, and tailored for developers rather than enterprises. It supports custom front- and backend development and offers both headless and headful UI integrations.

The platform is praised for its ease of use, customizability, and security features, with endorsements from various industry leaders. Stack Auth offers flexible pricing plans, including a free tier for individuals and scalable options for teams and growing businesses. Its open-source nature ensures developers can self-host and fully control their authentication systems.