Overview:
Stack Auth is an open-source authentication platform designed for developers who need to integrate user authentication into their applications quickly. It offers a managed service that can be used within minutes, supporting Next.js, React, and JavaScript frontends, along with any backend via its REST API. The platform allows users to optionally self-host and export their data at any time. It serves as a comprehensive solution for authentication, authorization, and user management for projects of varying sizes.
Core Features:
Authentication components: Supports OAuth, password credentials, and magic links for user sign-in.
User dashboard: A built-in interface for filtering, analyzing, and editing users.
Multi-tenancy & teams: Manages B2B customers with an organization structure designed for scaling.
Role-based access control (RBAC): Allows defining an arbitrary permission graph and assigning org-specific roles.
OAuth Connections: Manages access tokens for third-party APIs like Outlook and Google Calendar, including token refreshing and scope control.
Impersonation: Enables logging into a user's account for debugging and support purposes.
Use Cases:
Adding authentication to a new or existing Next.js project: Developers can use the installation wizard to set up sign-in, account settings, and email flows within minutes.
Managing B2B customers: Organizations can create team structures and assign roles to handle multi-tenant applications.
Building an internal user management tool: The built-in user dashboard replaces the need to build a custom admin interface for viewing and editing users.
Handling passwordless sign-in: Users can authenticate using passkeys with biometrics or security keys across devices.
Why It Matters:
Stack Auth provides a managed, open-source authentication layer that is free to use and allows for data portability to self-hosting. Its focus on developer experience—with idiomatic Next.js APIs, automatic email handling, and shared development keys—reduces the initial setup complexity. As a fully open-source solution (MIT and AGPL licensed), it serves as a transparent and customizable alternative to proprietary auth services for teams building web applications.
