Timeout Rate & Error Rate Alerts
Availability: Starter and above (timeout rate, error rate); see plan table below.
Standard down detection uses a quorum model: a monitor must fail in a majority of regions before it’s marked “down.” This works well for clear outages, but some failure modes are more subtle:
- An endpoint that sometimes responds but times out 80% of the time — technically “up” in the quorum sense, but obviously broken.
- A multi-region setup where one region consistently fails, but the other regions keep the monitor green.
Timeout rate and error rate alerts catch these scenarios.
Timeout Rate Alert
Fire an alert when more than X% of checks in the last 30 minutes timed out — regardless of quorum.
Use case: detecting a slow endpoint that is struggling under load but occasionally responds fast enough to stay “up.”
Configuration
Set a Timeout Rate Threshold (%) on the monitor edit screen → Advanced alerts. Leave blank to disable.
| Threshold | Meaning |
|---|---|
| 50% | Alert when the majority of checks time out |
| 80% | Alert only when most checks time out (high confidence) |
| 30% | Sensitive — alert on early signs of timeout pressure |
The alert fires at most once every 4 hours per monitor. Once the rate drops below the threshold and comes back, the cooldown resets.
Error Rate Alert (Degraded Mode)
Fire an alert when more than X% of all checks in the last 30 minutes failed — regardless of whether the quorum threshold for a full down alert was reached.
This is the “degraded” alert: your service is partially failing, but not fully down.
Use case: multi-region monitors where one region consistently returns errors. The monitor stays “up” in the dashboard, but real users in that region are experiencing failures.
Configuration
Set an Error Rate Threshold (%) on the monitor edit screen → Advanced alerts. Leave blank to disable.
How the 30-minute window works
Both alerts use a rolling 30-minute window of recent check outcomes. The window is tracked in memory and updated on every check. At least 5 checks must have occurred in the window before an alert can fire (to avoid false positives on new or infrequent monitors).
Plan availability
| Feature | Free | Starter | Team | Business | Enterprise |
|---|---|---|---|---|---|
| Timeout rate alert | — | ✅ | ✅ | ✅ | ✅ |
| Error rate (degraded) alert | — | ✅ | ✅ | ✅ | ✅ |