Production-Ready APIs in API

Lessons in this section

1. API Versioning

   Change an API without breaking its clients: spot breaking changes, serve /v1 and /v2 side by side, and retire old versions with Deprecation and Sunset headers.

2. API Authentication

   Make the API ask who is calling: protect endpoints with API keys, read and validate JWT bearer tokens, and answer 401 with WWW-Authenticate.

3. API Authorization and Security

   Check on every request that the caller is allowed to do this: own the record, have the role, carry the scope.

4. API Performance and Caching

   Make your API fast by not repeating work: fix N+1 queries, answer repeat visits with 304, and tell caches what they may keep.

5. Rate Limiting and Resilience

   Protect your API from too much traffic with rate limits and 429 Too Many Requests, and make clients cope with slow or failing services using retries and backoff.

6. API Monitoring and Logging

   Use structured logs, correlation ids, health checks and RED metrics to see what your API is doing and find bugs fast.

7. API Testing

   Write automated unit and integration tests that check status, headers and body on every change, so a fixed bug never comes back.

8. API Gateway

   Put one front door in front of your services so auth, limits, routing and header rules happen once, in one place.