Single Sign-On (SSO) and Federated Identity Management (FIM) are tools that enable access to multiple applications without requiring separate logins for each application. While they may seem similar, there are key differences between the two. SSO allows users to authenticate once in a single place to access apps within a single organization, while FIM enables organizations to access apps on different domains using a single set of credentials. Both tools improve user experience and security by reducing the number of passwords needed and simplifying identity management. To implement SSO and FIM for multiple enterprise customers, consider using a done-for-you authentication service like WorkOS.