Keycloak - Open Source Identity and Access Management for modern Applications and Services.
OpenLDAP - OpenLDAP Software is an open source implementation of the Lightweight Directory Access Protocol.
Auth0 - Auth0 is a program for people to get authentication and authorization services for their own business use.
FreeIPA - FreeIPA is an integrated security information management solution combining Linux (Fedora), 389...
Okta - Enterprise-grade identity management for all your apps, users & devices
Microsoft Active Directory - Active Directory is a special-purpose database \ 8212; it is not a registry replacement.