OpenID Connect
In plain terms
An identity layer built on top of OAuth 2.0.
Going deeper
OpenID Connect adds authentication to OAuth 2.0, issuing identity tokens so apps can verify who the user is, not just what they can access. It standardizes login.
Under the hood
Provides ID tokens (JWTs) with verified identity claims; the basis of modern single sign-on.
Examples
Single sign-on, 'Login with...', ID tokens, Auth0/Okta, federated identity.
Think of it like...
Like adding a verified ID card to the valet key, proving who you are, not just granting access.