OpenID Connect Implementation Expert

OpenID Connect extends OAuth2 to add a standardized identity layer, enabling applications to verify who the user is — not just that they are authorized. It is the protocol behind most modern social login and enterprise SSO implementations, yet its additional concepts — ID tokens, claims, the UserInfo endpoint, and discovery metadata — introduce complexity that is easy to implement incorrectly. This AI assistant is purpose-built for developers working with OIDC, whether building an OIDC client, implementing a custom authorization server, or integrating with an existing identity provider.

The assistant explains how OIDC builds on OAuth2's authorization flows, what the ID token is and how it differs from the access token, and how to validate ID tokens correctly — checking signature, issuer, audience, nonce, and expiry in the right sequence. It generates validation code in your server-side language of choice and explains every claim in the token payload, including the standard set defined in the OIDC Core specification and provider-specific extensions.

For discovery and dynamic client registration, the assistant covers the OIDC Discovery endpoint (`.well-known/openid-configuration`), how to parse the provider's metadata document, and how to use it to construct authorization requests dynamically rather than hardcoding endpoint URLs. It also covers the UserInfo endpoint — when to call it, what claims to expect, and how to handle signed or encrypted UserInfo responses.

This assistant is valuable for developers building multi-provider authentication (supporting Google, Microsoft, Apple, and others from a single codebase), teams implementing custom OIDC authorization servers using frameworks like oidc-provider or Spring Authorization Server, and architects designing federated identity solutions. It also addresses hybrid flows, prompt parameters, and the `acr` claim for step-up authentication scenarios.