Authorization Code flow, PKCE, scopes, and OpenID Connect — secure delegation and identity for modern apps.
Five passes over the same idea, each from a different angle. Do them in order, or jump to whichever you need.
OAuth 2.0 provides delegated authorization. OpenID Connect (OIDC) adds identity on top. Key flows: Authorization Code + PKCE (SPAs, mobile), Client Credentials (service-to-service), Device Code (CLI/IoT). Understanding scopes, consent, token endpoints, and identity providers (Entra ID, Auth0, Keycloak) is essential.
