API Design Patterns: Building Scalable APIs

Well-designed APIs are the foundation of modern software systems. They are the contracts between different components. This guide explores patterns and practices for building scalable, maintainable APIs that developers love to use.

REST API Design Principles

• Use standard HTTP methods (GET, POST, PUT, DELETE) correctly.
• Design resources, not actions/verbs. URIs should be nouns (e.g., /users/123).
• Use proper HTTP status codes (200 OK, 201 Created, 400 Bad Request, 401 Unauthorized, etc.).
• Implement pagination (cursor-based is better than offset-based) for large datasets.
• Version your API explicitly (e.g., /v1/...) to avoid breaking changes.

Performance Optimization

Performance features should be built-in. Implement caching strategies (ETags, Cache-Control headers). Use rate limiting (Token Bucket algorithm) to prevent abuse. Optimize response payloads using compression (gzip/brotli) and consider GraphQL if clients notoriously over-fetch data.