oauth-expert

Implement OAuth 2.0 Authorization Code flow with PKCE for a SPA by configuring public clients to generate code verifiers and challenges, then exchanging the authorization code for tokens. This ensures secure access without exposing client secrets.

JWT validation requires thorough claim checks for issuer, audience, expiration, and not-before timestamps. Robust JWT validation ensures tokens are legitimate, unexpired, and authorized for the intended resource server.

Refresh token rotation issues a new refresh token on every use, invalidating the previous one to limit compromise windows. Combined with secure token storage, it prevents replay attacks and maintains session continuity.

OAuth 2.0 supports machine-to-machine services through client credentials flow, enabling secure server-to-server authorization without user intervention. It applies to web, mobile, and SPA environments requiring access control.

OpenID Connect is needed for identity federation when authentication and user identity claims are required alongside OAuth 2.0 authorization. It enables multi-provider interoperability and federated identities across applications.

The BFF pattern manages tokens server-side to avoid exposing them to the browser, ideal for SPAs needing secure token revocation. It leverages backend components to handle authorization flows and credential management securely.