Authentik is an open-source Identity Provider (IdP) that enables self-hosted user authentication, single sign-on (SSO), and access controls. It supports industry-standard protocols such as SAML2, OAuth2, OpenID Connect, and LDAP, allowing for integration with a wide range of applications and services. Authentik offers an extensible "flow" system for configurable user journeys, deployment methods including Docker Compose, Kubernetes, and Terraform, and granular policies for access controls. By choosing Authentik over alternatives like Azure/Entra ID or Keycloak, organizations can gain control over their identity infrastructure, simplify single sign-on, and maintain robust governance while reducing complexity and costs compared to managed services.