Terminology REST (Representational State Transfer) has become the de facto standard for building web APIs . Its stateless nature, resource-based approach, and standard HTTP methods (GET, POST, PUT, DELETE) provide a clean, predictable interface for client-server communication. ✅ Authentication & Security API security starts with robust authentication mechanisms. From API keys and JWT tokens to OAuth 2.0 flows, choosing the correct authentication method is critical for protecting your endpoints while maintaining usability. ✅ API Design Principles Good API design follows predictable patterns: Use nouns for resource endpoints (/users instead of /getUsers) Implement consistent error handling and status codes Version your APIs to maintain backward compatibility Design with scalability in mind, considering rate limiting and caching strategies ✅ Documentation Standards Clear, comprehensive documentation is the cornerstone of API adoption. OpenAPI (formerly Swagger) has emerged as the industry standard for describing REST APIs, enabling both human-readable documentation and automated code generation. ✅ Testing & Monitoring A robust API testing strategy encompasses: Unit tests for individual endpoints Integration tests for API workflows Performance testing under load Continuous monitoring for availability and response times These concepts form the foundation of modern API development.