An authentication token is a cryptographically signed string that encapsulates claims about the user, such as their identity, roles, or permissions. Tokens verify identity without requiring an active session on the server and provide a secure way to manage access control for applications' resources and APIs. They are often stored in secure HTTP-only cookies to prevent unauthorized access and client-side attacks like XSS. The main types of authentication tokens include Access Tokens, Refresh Tokens, and JSON Web Tokens (JWTs). Authentication tokens offer benefits such as Single Sign-On (SSO), temporary access control, granular access control, enhanced security, microservices authentication, and improved user experience. JWTs are a popular type of authentication token that is compact, URL-safe, and self-contained. To generate and secure JWTs, follow best practices such as using HTTPS, setting expiration times, storing tokens securely, avoiding sensitive data in tokens, implementing token revocation, and rotating keys. WorkOS offers a streamlined way to support enterprise SSO in applications by connecting with major identity providers like Okta and Microsoft Entra.