🔗 SECTION 4: API Design (7 Qs) 1. Explain REST principles. Stateless, resource-based URIs, HTTP verbs, uniform interface, cacheable responses. 2. How to version APIs? Via URL /api/v1/users/ or header Accept: application/vnd.company.v1+json. 3. How to secure APIs? Use JWT/OAuth2, HTTPS, rate limiting, API key verification. 4. Difference between PUT and PATCH. PUT replaces full resource, PATCH updates part. 5. Write Flask API endpoint.