Keycloak is an open-source IAM server providing single sign-on, user federation, and centralized authentication and authorization using OIDC, OAuth 2.0, and SAML.

36.4k stars8.9k forksApache-2.0last commit Actively maintained

Managed cloud identity platform offering SSO (SAML/OIDC), user directory and provisioning (SCIM/LDAP), MFA/WebAuthn, conditional access policies, application proxy and federation. Provides APIs and integrations for app/API authentication, authorization and remote access.
Keycloak is an open-source IAM server providing single sign-on, user federation, and centralized authentication and authorization using OIDC, OAuth 2.0, and SAML.

36.4k stars8.9k forksApache-2.0last commit Actively maintained
Authelia is an open-source IAM and authentication server providing SSO, MFA, and access control for web apps, with OpenID Connect/OAuth 2.0 and reverse-proxy integration.

28.7k stars1.5k forksApache-2.0last commit Actively maintained
ZITADEL is an open source IAM/CIAM platform providing SSO, MFA, OIDC/OAuth2, SAML, user management, and multi-tenant organizations with audit logging.
14.9k stars1.3k forksAGPL-3.0last commit Actively maintained
Open-source authentication and authorization infrastructure with OIDC/OAuth 2.1, SAML SSO, multi-tenancy, MFA, and RBAC for SaaS and AI apps.
14.5k stars1.2k forksMPL-2.0last commit Actively maintained
Casdoor is an open-source, UI-first IAM/SSO platform supporting OAuth 2.0, OIDC, SAML, LDAP, SCIM, WebAuthn and MFA, with an admin web UI and SDKs.
14.3k stars1.8k forksApache-2.0last commit Actively maintained
Pocket ID is a simple self-hosted OpenID Connect (OIDC) provider that lets users sign in to apps using passkeys instead of passwords.

9k stars304 forksBSD-2-Clauselast commit Actively maintained
Tinyauth is a lightweight auth middleware that adds a login screen, OAuth, or LDAP authentication in front of your apps via common reverse proxies.

8.2k stars264 forksAGPL-3.0last commit Actively maintained
Kanidm is a secure identity management platform providing SSO, passkeys (WebAuthn), and integrations like OAuth2/OIDC, RADIUS, and LDAP gateway for legacy apps.

5.3k stars354 forksMPL-2.0last commit Actively maintained
VoidAuth is a self-hosted SSO provider with OpenID Connect, ForwardAuth proxy auth, and built-in user and group management plus MFA and passkeys.

2.5k stars100 forksAGPL-3.0last commit Actively maintained
Open-source Auth0/Clerk/Firebase Auth alternative with passkeys, MFA, SSO (OIDC/SAML), user management portal, and extensible auth flows for web and mobile apps.

2k stars125 forksApache-2.0last commit Actively maintained
Mozilla Accounts (FxA) is an account and authentication service used by Mozilla clients, providing login, session management, and account-related APIs for Mozilla products.

685 stars236 forksMPL-2.0last commit Actively maintained
Lightweight Go-based authentication gateway that provides unified SSO for Plex, Jellyfin, and Emby users with OIDC, MFA and an admin console. Runs in Docker and stores profiles in Postgres.
98 stars1 forksGPL-3.0last commit Actively maintained
Stackspin is an open source platform that bundles common team collaboration apps with single sign-on, centralized user management, backups, and monitoring for admins.

Activity unknown
Every option on this page is open source and free to run on your own hardware, so you own the data and there is no subscription to cancel. 12 of 13 shipped a commit in the last six months. Licences in this list: Apache-2.0, AGPL-3.0, MPL-2.0, BSD-2-Clause, GPL-3.0. In exchange you take on hosting, backups and updates yourself.
Browse everything in Identity & Access Management (IAM).