Use maintained OAuth/OIDC libraries and provider-recommended flows; validate state and redirect URIs and request minimum scopes.

How to apply it

Protect refresh tokens server-side where required. Enterprise features may include SAML/OIDC SSO, SCIM, MFA, domain verification, and organization session policy. Account linking needs explicit trust rules; deprovisioning revokes sessions and access.

Worked example

SCIM deactivation marks membership inactive, revokes sessions, and creates an audit event while preserving organization-owned records per policy.

Common mistakes to avoid

Putting client secrets in browser code or merging identities solely because email strings match.

Practice task

Implement this concept in the capstone. Add one positive test, one negative or failure-path test, and a short note explaining the trade-off you chose.