OpenID Connect Core 1.0
Sign-in with Google/Apple/GitHub all use OIDC. If your app authenticates users via a third party, you're using OIDC whether you know it or not.
What It Defines
Identity layer on top of OAuth 2.0. Adds ID tokens (JWT), UserInfo endpoint, standard claims (sub, email, name), and a defined authentication flow. Used for login-with-X and SSO.
Canonical (Normative)
Convenient (Practical)
Related References
Canonical home for OpenID Connect specifications: OIDC Core, Discovery, Session Management, Dynamic Registration, and related profiles. Separate from the OAuth IETF work.
Related Specs
The foundation of modern app auth: third-party login, API authorization, SSO, and machine-to-machine access all use OAuth 2.0.
JWTs are the token format for OIDC ID tokens and many OAuth implementations. Understanding the structure and security tradeoffs is essential.
When your app verifies a JWT from an identity provider, it fetches the public key as a JWK from the OIDC discovery endpoint.
SIWE is the Web3 equivalent of Sign-In with Google. Enables dApps to authenticate users via their Ethereum address without a password, using their wallet signature.