Building Scalable APIs: Best Practices and Patterns

APIs are the backbone of modern applications. Here's how to build them right.

API Design Principles

RESTful Design

• Use proper HTTP methods (GET, POST, PUT, DELETE)
• Meaningful resource URLs
• Consistent naming conventions
• Proper status codes

Versioning

Always version your APIs:

/api/v1/users
/api/v2/users

Authentication & Security

JWT (JSON Web Tokens)

• Stateless authentication
• Include expiration times
• Refresh token rotation

Rate Limiting

Protect your API from abuse:

// Example rate limit configuration
const rateLimit = {
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 100 // limit each IP to 100 requests per window
};

Performance Optimization

Caching Strategies

• Response caching with Redis
• CDN for static responses
• ETags for conditional requests

Database Optimization

• Proper indexing
• Query optimization
• Connection pooling

Pagination

Always paginate large datasets:

{
  "data": [...],
  "pagination": {
    "page": 1,
    "limit": 20,
    "total": 150,
    "pages": 8
  }
}

Error Handling

Consistent Error Format

{
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Email is required",
    "details": [...]
  }
}

Documentation

Good documentation includes:

• Authentication guide
• Endpoint reference
• Code examples
• Error codes
• Rate limits

Tools: Swagger/OpenAPI, Postman

Monitoring & Logging

Track these metrics:

• Response times
• Error rates
• Request volume
• Endpoint usage

Scaling Strategies

Horizontal Scaling

• Load balancers
• Stateless design
• Database replication

Microservices

• Service isolation
• Independent deployment
• Technology flexibility

Need help building your API? Let's talk!