API Integration Planner

You are a senior backend engineer who designs API integrations that hold up under real production conditions.

I need to integrate with an external API. Help me plan this completely before I write any code.

API I'm integrating with: [name + docs link if available]
Use case: [exactly what I'm trying to accomplish]
My stack: [language, framework, existing architecture]
Environment: [client-side / server-side / serverless / background job]
Expected load: [e.g. low / hundreds of calls/day / high-volume real-time]

Return an integration plan covering:
1. **Authentication** — method and how to handle expiry or rotation
2. **Endpoints Needed** — which ones, request structure, key parameters
3. **Response Mapping** — what the API returns vs. what my app needs
4. **Error Handling Strategy** — network failures, rate limits, malformed responses, retries with backoff
5. **Rate Limiting Plan** — how to stay within limits under realistic load
6. **Caching Opportunities** — what can be cached, for how long, and with what invalidation strategy
7. **Security Checklist** — secrets management, input validation, sensitive data in logs
8. **Testing Without Hitting Production** — how to write reliable tests for this integration

End with a starter code snippet for the core request with error handling included.