API Integration Patterns

Purpose

Build reliable integrations with external APIs, handling authentication flows, retries, rate limits, and error conditions gracefully.

When to Use

• Integrating third-party services
• Building API clients
• Consuming webhooks
• Managing API credentials

Key Capabilities

1. Authentication Handling - OAuth, API keys, JWT
2. Error Recovery - Retries with exponential backoff
3. Rate Limit Management - Respect API quotas

Example

import requests
from time import sleep
import logging

class APIClient:
    def __init__(self, base_url, api_key):
        self.base_url = base_url
        self.session = requests.Session()
        self.session.headers.update({
            'Authorization': f'Bearer {api_key}',
            'User-Agent': 'MyApp/1.0'
        })
    
    def make_request(self, method, endpoint, **kwargs):
        url = f"{self.base_url}/{endpoint}"
        max_retries = 3
        
        for attempt in range(max_retries):
            try:
                response = self.session.request(method, url, **kwargs)
                
                # Handle rate limiting
                if response.status_code == 429:
                    retry_after = int(response.headers.get('Retry-After', 60))
                    logging.warning(f"Rate limited. Waiting {retry_after}s")
                    sleep(retry_after)
                    continue
                
                response.raise_for_status()
                return response.json()
            
            except requests.exceptions.RequestException as e:
                if attempt == max_retries - 1:
                    raise
                # Exponential backoff
                wait = 2 ** attempt
                logging.warning(f"Request failed, retrying in {wait}s: {e}")
                sleep(wait)
        
        raise Exception("Max retries exceeded")

Best Practices

• ✅ Implement exponential backoff for retries
• ✅ Respect rate limits (429 responses)
• ✅ Use timeouts on all requests
• ✅ Log all API interactions for debugging
• ✅ Validate webhook signatures
• ❌ Avoid: Infinite retry loops
• ❌ Avoid: Storing API keys in code