goauthentik/authentik

authentik is an open-source Identity Provider (IdP) designed for modern Single Sign-On (SSO) solutions. It supports multiple authentication protocols like SAML, OAuth2/OIDC, LDAP, and RADIUS, making it suitable for self-hosting in environments ranging from small labs to large production clusters. It's ideal for organizations looking to replace commercial IdPs with a robust, self-hosted alternative.