Building Scalable APIs: Lessons from 150+ Integrations

After integrating with over 150 third-party APIs - from health devices to payment gateways - we've learned what separates robust integrations from fragile ones. Here are the patterns and practices that have proven most valuable.

Design for Failure

Every external API will fail eventually. Networks go down, rate limits get hit, and providers push breaking changes. The key is building resilience from day one: circuit breakers, retry logic with exponential backoff, and graceful degradation.

Authentication Patterns That Scale

• OAuth 2.0 for user-authorized access with proper token refresh handling
• API keys with rotation strategies and secure storage
• JWT tokens with appropriate expiration and revocation capabilities
• Webhook signatures for secure event notifications

Performance Optimization

Caching, connection pooling, and request batching can dramatically improve performance. We've seen 10x improvements in throughput by implementing intelligent caching strategies and reducing redundant API calls.

Monitoring and Observability

You can't fix what you can't see. Comprehensive logging, metrics collection, and alerting are essential. Track latency percentiles, error rates, and upstream availability to catch issues before they impact users.