uptimeMonitorUptime Monitoring for APIs: Why Status Codes Aren't Enough
Your API can return 200 OK and still be completely broken. Here's how to monitor APIs properly and catch the failures that status codes miss.
Uptime Monitoring for APIs: Why Status Codes Aren't Enough
Your API health check returns 200. Everything's fine, right? Not necessarily. A 200 status code means your server responded. It doesn't mean it responded correctly.
The False Sense of Security
Real scenarios where an API returns 200 but is effectively broken:
- Empty Response Bodies — Returns 200 with
{}instead of actual data - Cached Stale Data — Serves hours-old data from cache
- Partial Failures — Aggregates from 3 services, one is down, results incomplete
- Slow but "Successful" — Response time degraded from 200ms to 8 seconds
- Wrong Data Format — Deployment changed response schema, mobile apps crashing
How to Monitor APIs Properly
- Check Response Body Content — Validate the response contains expected data
- Monitor Response Time — A slow API is a broken API from the user's perspective
- Validate Response Headers — Check Content-Type, cache, CORS headers
- Monitor from Multiple Regions — An API can be fast in US-East and broken in APAC
- Test Authentication Flows — Monitor authenticated endpoints too
- Monitor Dependent Services — A chain is only as strong as its weakest link
Response Time Baselines
| Endpoint Type | Expected | Warning | Critical |
|---|---|---|---|
| Health check | <50ms | >200ms | >1s |
| Simple read | <200ms | >500ms | >2s |
| Complex query | <500ms | >1.5s | >5s |
Status codes are the beginning of monitoring, not the end.
Written by
UptimeGuard Team
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