Keycloak

Keycloak is an open-source Identity and Access Management (IAM) server for modern applications and services. It centralizes authentication and authorization so applications can rely on standards-based SSO instead of implementing login, user storage, and session management.

Key Features

• Single sign-on and single sign-out across multiple applications
• Support for standard protocols: OpenID Connect, OAuth 2.0, and SAML 2.0
• Identity brokering and social login via configurable identity providers
• User federation with LDAP and Active Directory, with extensible provider support
• Admin console for managing realms, clients, users, roles, sessions, and policies
• Account management console for end users (profile, password changes, session management, and 2FA)
• Fine-grained authorization services for policy-based access control

Use Cases

• Centralized SSO for internal apps, APIs, and microservices
• Replacing custom authentication with standards-based identity and token issuance
• Integrating enterprise directories (LDAP/AD) and external identity providers into one login flow

Limitations and Considerations

• Operating securely at scale requires careful configuration of realms, clients, token lifetimes, and session settings
• Some advanced deployments may require external databases and clustering planning for high availability

Keycloak is widely used as a central identity provider to standardize authentication and access control across heterogeneous systems. It reduces application complexity while enabling consistent security policies and user management in one place.