SCIM (System for Cross-domain Identity Management) is a protocol that provides a standard way for identity providers and service providers to communicate. It defines two main resource types — users and groups. SCIM groups are collections of users with something in common, usually used for role-based access control. They simplify user management by making it easier for IT admins to assign rights, roles, and responsibilities across different apps or services. However, inconsistencies among identity providers can introduce complexities and security risks. WorkOS' Directory Sync provides a more unified and secure SCIM provisioning solution that handles each provider's intricacies and quirks, ensuring smooth operation and minimizing security issues.