Keycloak is an open-source identity and access management (IAM) platform from Red Hat. It provides centralized authentication for applications—Single Sign-On (SSO), user management, role-based access control (RBAC), federation with LDAP/Active Directory, and integration with external identity providers (Google, GitHub, OIDC). Keycloak speaks standard protocols: OAuth2, OpenID Connect (OIDC), SAML. Applications redirect users to Keycloak for login, Keycloak handles credential verification, returns tokens, applications validate tokens and grant access.