Integrating OpenID Connect (OIDC) Authentication in Angular and React

OpenID Connect (OIDC) is an identity layer on top of OAuth 2.0. If you’ve used “Sign in with Google/Microsoft/Okta/Auth0”, you’ve already used OIDC. In modern single-page apps (SPAs), the best practice is:

• Authorization Code Flow + PKCE
• Store tokens in memory (avoid localStorage when possible)
• Use the provider’s well-known discovery document
• Protect routes and attach access tokens to API calls

This guide shows an end-to-end setup for both Angular and React.