What is the Difference Between LDAP and Single Sign-On?

LDAP and SSO serve different but complementary roles in authentication. LDAP is a protocol for accessing and managing directory information like usernames, emails, and group memberships in a centralized location. SSO is an authentication mechanism that allows users to access multiple applications with a single login, using protocols like SAML, OAuth, and OpenID Connect. LDAP focuses on defining who users are and what they can access, while SSO verifies identity to grant access across multiple systems. Organizations often use both together, with LDAP as the user directory backbone and SSO providing the access layer. The choice depends on specific needs: LDAP excels at centralized directory management and legacy app support, while SSO improves user experience and security by reducing password fatigue.