REST API Design: Best Practices and Common Mistakes

# REST API Design: Best Practices and Common Mistakes A well-designed API is a joy to use. A poorly designed one causes frustration and bugs. Here's how to design APIs that developers love. ## Core Principles ### 1. Use Nouns, Not Verbs ``` ✅ GET /users ❌ GET /getUsers ``` ### 2. Use HTTP Methods Correctly - GET: Read data - POST: Create data - PUT: Update (replace) data - PATCH: Partial update - DELETE: Remove data ### 3. Use Proper Status Codes - 200: Success - 201: Created - 400: Bad Request - 401: Unauthorized - 404: Not Found - 500: Server Error ## Response Format ### Consistent Structure Always return data in a consistent format with proper error objects including code, message, and details. ### Pagination For list endpoints, include pagination metadata with total items, page number, items per page, and total pages. ## Versioning ### URL Versioning Most common and explicit: `/api/v1/users` ### Header Versioning Cleaner URLs but less visible: `Accept: application/vnd.api+json;version=1` ## Authentication ### JWT (JSON Web Tokens) Stateless, scalable, good for SPAs and mobile apps. ### API Keys Simple, good for server-to-server communication. ### OAuth 2.0 For third-party access and complex authorization. ## Documentation ### OpenAPI/Swagger Standard for API documentation with interactive testing. ### Examples Always include request/response examples. ## Common Mistakes 1. **Not using HTTPS**: Always encrypt in production 2. **Exposing sensitive data**: Be careful what you return 3. **No rate limiting**: Protect against abuse 4. **Poor error messages**: Help developers debug ## Conclusion Good API design takes time but pays dividends in developer experience and reduced support burden.