OpenID Connect (OIDC) is an authentication protocol built on top of OAuth 2.0, designed to facilitate secure and seamless user identity verification across multiple applications using JSON Web Tokens (JWTs). By enabling single sign-on (SSO) and identity federation, it allows users to log into various services with credentials from trusted identity providers like Google or Facebook. OIDC bridges the gap left by OAuth 2.0, which focuses on authorization rather than authentication, by introducing an ID token that includes user identity claims. The OIDC flow involves a client application (Relying Party), an OIDC Provider for authentication, and the end-user seeking access. Different methods such as authorization code, implicit, and hybrid flows can be used depending on security needs. OIDC enhances security by centralizing authentication, improving privacy, and supporting interoperability with existing systems, making it scalable and versatile. Implementing OIDC requires attention to security requirements, integration capabilities, and provider dependence, with platforms like Descope offering simplified integration options for developers.