Flapping detection
How Lemwatch suppresses monitors that flip up/down repeatedly instead of paging you every flip.
Quick answer
A monitor is "flapping" when its status flips 3+ times in 15 minutes. Lemwatch sends one summary alert instead of paging you per flip.
What it does
- Tracks status transitions in a 15-minute rolling window
- Marks the monitor flapping at 3+ transitions
- Sends one "flapping detected" alert, then goes quiet
- Sends a "flapping resolved" alert once stable for 15 minutes
Where to find it in Lemwatch
Site → Settings → Alert accuracy → Flap detection.
How to tune it
- Open Alert accuracy for the site.
- Adjust Transitions to flap (default 3) — lower = more aggressive.
- Adjust Rolling window (default 15 min) — shorter = catches faster flaps.
- Optionally route flap alerts to a lower-priority channel.
- Save.
FAQ
Do I still get the underlying down alert?
Yes — the first down alert always fires. Flapping suppression starts on the third transition.
Does flapping affect uptime %?
No. Every transition is recorded in history; only alerting is suppressed.
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