Authentication

Self-hosted authentication and identity management is one of the highest-stakes categories in the open source ecosystem. Your auth system controls who accesses your application, what permissions they have, and how sessions and tokens are managed -- a third-party outage or breach directly impacts every user. Open source alternatives to Auth0, Okta, and Clerk, such as Keycloak, Authentik, and Ory, provide OAuth 2.0, OpenID Connect, SAML, multi-factor authentication, and user management on your own infrastructure. Keycloak, backed by Red Hat, is the most widely deployed open source identity provider, used by government agencies and Fortune 500 companies for single sign-on across dozens of internal applications. The 2025 Okta and Auth0 pricing increases pushed many teams to evaluate self-hosted alternatives, finding that tools like Authentik provide comparable functionality with modern UIs and straightforward Docker deployment. Self-hosted auth eliminates vendor dependency for your most critical security layer and gives you direct control over session policies, password requirements, and brute-force protection rules. It also removes per-MAU pricing that scales unfavorably -- a self-hosted Keycloak instance handles millions of authentications without usage-based costs. Kubernetes operators for Keycloak and Ory make high-availability deployment achievable with standard DevOps practices. When evaluating self-hosted authentication, prioritize protocol support (OIDC, SAML, LDAP), social login provider availability, multi-factor authentication options, and the quality of admin UIs for user management. Self-hosted identity infrastructure gives you the ability to audit every authentication event, enforce custom security policies, and guarantee uptime independently of any vendor.