How do REST APIs handle authentication and authorization?

Short answer: Common methods: API Keys → Simple tokens. Basic Auth → Username & password (not secure without HTTPS). OAuth 2.0 / OpenID Connect → Standard protocols for secure access. JWT (JSON Web Tokens) → Widely used for stateless authentication.

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.