Building Great APIs
APIs are the backbone of modern software. Here's how to design and build APIs that developers actually want to use.
REST API Design Principles
Use Proper HTTP Methods: - GET: Retrieve resources - POST: Create resources - PUT: Update resources (full) - PATCH: Update resources (partial) - DELETE: Remove resources
Resource Naming:
`
Good:
GET /users
GET /users/123
GET /users/123/orders
Bad:
GET /getUsers
GET /user_list
POST /createNewUser
`
Status Codes Matter
Common Codes: - 200: Success - 201: Created - 400: Bad Request - 401: Unauthorized - 403: Forbidden - 404: Not Found - 500: Server Error
Request/Response Design
Consistent Response Format:
`json
{
"data": { },
"meta": {
"page": 1,
"total": 100
},
"errors": []
}
`
Pagination: - Use limit and offset - Return total count - Include next/prev links
Authentication & Security
Options: - JWT tokens (stateless) - OAuth 2.0 (third-party) - API keys (simple cases)
Security Checklist: - HTTPS always - Rate limiting - Input validation - SQL injection prevention - CORS configuration
Versioning Strategies
Options: - URL path: /api/v1/users - Header: Accept: application/vnd.api.v1+json - Query parameter: /users?version=1
Recommendation: URL versioning for simplicity.
Documentation
Essential Docs: - Authentication guide - Endpoint reference - Request/response examples - Error codes - Rate limits
Tools: - OpenAPI/Swagger - Postman - ReadMe - Redoc
GraphQL Considerations
When to Use GraphQL: - Complex, interconnected data - Multiple clients with different needs - Rapid iteration - Mobile apps (bandwidth optimization)
When REST is Better: - Simple CRUD operations - Caching requirements - File uploads - Team familiarity
Error Handling
Good Error Response:
`json
{
"error": {
"code": "VALIDATION_ERROR",
"message": "Email is invalid",
"field": "email",
"documentation_url": "https://..."
}
}
`
Performance Tips
- Use pagination
- Implement caching (ETags, Cache-Control)
- Enable compression (gzip)
- Use connection pooling
- Consider async operations for long tasks
Conclusion
Good APIs are intuitive, consistent, and well-documented. Follow these practices, and developers will thank you.
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