1 Best Open Source Auth0 Alternatives

Auth0, now part of Okta, is an identity-as-a-service platform that handles login, sign-up, multi-factor authentication, and user management for applications. Developers integrate it via SDKs instead of building authentication from scratch, and it supports social logins, single sign-on, and role-based access control out of the box.

Organizations look for open-source alternatives to Auth0 mainly because of pricing that scales with monthly active users, which can become expensive as an application grows. Others want to keep user credentials and identity data on their own infrastructure rather than a third-party service, either for compliance reasons or to avoid depending on an external provider for something as central as login.

Authelia is one open-source option, though it takes a different approach than Auth0. Rather than being an embedded identity SDK, it works as a self-hosted authentication and authorization server that sits in front of applications through a reverse proxy, adding single sign-on and multi-factor authentication to services that may not have built-in auth support. It fits well for teams protecting a set of internal tools or self-hosted apps rather than building a customer-facing product from scratch.

When comparing options, check whether the alternative supports the specific protocols your application needs, such as OAuth2, OpenID Connect, or SAML, since not all self-hosted tools implement every standard. Consider how much integration work is required, since replacing an SDK-based service like Auth0 with a proxy-based tool like Authelia can mean restructuring how your application handles sessions. Also evaluate the operational burden of running and securing your own identity server, since a misconfiguration here has higher stakes than most other self-hosted services.