An uptime percentage alert rule fires when your monitor's uptime over a specified time window drops below a threshold. This is ideal for SLA-based alerting and reducing false positives from one-off check failures.
Instead of evaluating each check in isolation, PulseAPI looks at the overall uptime percentage across all checks in the time window. If the percentage drops below your threshold, the rule fires.
This means a single failed check out of 1,440 (one minute of downtime in a day) doesn't trigger a Critical alert — you can tune the threshold to match your SLA commitments.
99.9).| SLA | 24h Window Threshold | 7d Window Threshold |
|---|---|---|
| 99.9% ("three nines") | < 99.9% | < 99.9% |
| 99.5% | < 99.5% | < 99.5% |
| 99% | < 99% | < 99% |
24-hour window — more sensitive; catches degradation quickly. Good for critical services where even a brief dip below SLA is worth alerting on.
7-day window — less sensitive to short outages; catches sustained degradation. Good for SLA reporting and non-critical services.
30-day window — SLA reporting threshold; only fires on sustained, long-term degradation. Use as a summary metric rather than an operational alert.
| Per-Check Rule | Uptime Percentage Rule | |
|---|---|---|
| Fires on | Every single failure | Pattern of failures |
| False positive rate | Higher | Lower |
| Detection speed | Faster (fires on first failure) | Slower (fires after enough failures accumulate) |
| Best for | Mission-critical endpoints | SLA monitoring; reducing alert noise |
Use both: a per-check Critical rule for immediate notification on failures, plus a per-period Uptime rule for sustained degradation tracking.
Still have questions? Contact support.