Single Sign-On (SSO) simplifies user access across multiple applications with one set of credentials, enhancing user experience and security. The article demystifies key authentication protocols: OAuth 2.0, OIDC (OpenID Connect), and SAML. OAuth 2.0, primarily an authorization framework, allows applications to access resources without sharing user passwords, while OIDC builds on OAuth to authenticate users with ID tokens in JSON format. SAML, using XML, is favored in enterprise settings for federated authentication, allowing users to log into multiple applications with a single identity. Each protocol has its strengths and complexities, with OAuth focusing on authorization, OIDC on authentication, and SAML offering rich features for enterprise use. The article suggests that while understanding these protocols is beneficial, third-party vendors like WorkOS can provide streamlined, secure, and efficient SSO solutions, potentially easing implementation challenges for organizations.