Authentication, Authorization, Tokens, API Keys, and OAuth Concepts
Secure RESTful APIs by understanding identity, access control, and common authentication mechanisms.
Inside this chapter
- Authentication vs Authorization
- Common Auth Mechanisms
- Authorization Patterns
- Security Headers and Transport
- Business Example
Series navigation
Study the chapters in order for the clearest path from REST basics to advanced API design, operations, and production readiness. Use the navigation at the bottom to move smoothly across the full tutorial series.
Authentication vs Authorization
Authentication answers who the client is. Authorization answers what the client is allowed to do. Both matter, and many junior engineers mix them up. A user may be authenticated but still forbidden from deleting another user’s records.
Common Auth Mechanisms
- API keys for simple service access
- Bearer tokens for session-like stateless auth
- JWT-based approaches in many ecosystems
- OAuth and OpenID Connect for delegated or federated identity
Authorization Patterns
Authorization may be role-based, permission-based, resource-ownership based, or policy-based. API designers should think in terms of business rules, not just whether a token exists.
Security Headers and Transport
RESTful APIs handling sensitive data should use HTTPS, protect tokens carefully, validate scopes or roles, and avoid leaking sensitive information in logs or error responses.
Business Example
An HR platform may let employees view their own records, managers approve leave for their teams, and administrators manage organization-wide settings. Good API authorization reflects those distinctions exactly.