OpenID and OAuth are two distinct protocols used for digital identity and access management, with OpenID primarily focused on user authentication and OAuth on delegated authorization. OpenID allows users to log into multiple websites using a single identity provider, simplifying the sign-in process but potentially introducing privacy and security risks if the provider is compromised. In contrast, OAuth enables users to grant third-party applications limited access to their data without exposing credentials, offering safer delegated authorization but requiring careful management of permissions and user education. OAuth 2.0, the latest version, enhances security and simplifies developer workflows, establishing itself as a flexible industry standard for API access. OpenID Connect (OIDC) merges elements from both protocols, offering seamless single sign-on and authorized access to user data by building on OAuth 2.0 with an identity layer. While OpenID has lost traction to social logins, OAuth is widely adopted for API integration and third-party app access, with developers needing to consider the specific use cases and trade-offs of each protocol to ensure a balance of simplicity, security, and functionality.