TL;DR
Third-party APIs extend your attack surface. Store credentials securely using environment variables, request only necessary permissions, validate all responses, and plan for failures. 4 critical items must be fixed before launch, 6 important items within the first week, and 4 recommended items when you can.
Quick Checklist (5 Critical Items)
Credential Management 4
Request Security 4
Error Handling 3
Monitoring and Maintenance 3
You Inherit Their Risks
Every third-party API you integrate becomes part of your attack surface. If they get compromised, your users' data could be at risk. If they go down, your app might break. If they change their API, your integration could fail.
Treat third-party integrations as untrusted. Validate everything they return, handle their failures gracefully, and have a plan for when they let you down.
How often should I rotate API keys?
Rotate API keys at least annually, or immediately if you suspect compromise. Some services support automatic rotation. Build key rotation into your processes before keys expire or get compromised.
Should I proxy third-party APIs through my backend?
Yes, when possible. Proxying through your backend keeps API keys off the client, lets you add rate limiting and caching, and gives you control if the third-party API changes. The main trade-off is added latency.
What if a third-party API requires client-side access?
Use keys with restricted permissions when client-side access is required. Accept that these keys can be extracted. Monitor for abuse and rate limit requests. Consider if there is a server-side alternative.