Docs / Platform
Monitors
A monitor captures a page on schedule, pixel-diffs every run against the previous one, keeps a visual archive, and emails you the moment the change crosses your threshold.
Creating a monitor
Add a URL on the Monitors page. The first check runs within a minute and becomes the baseline. Captures are always full-page, fresh (never cached), with ads blocked and lazy-loaded images settled.
- ▸Daily monitors run at a fixed UTC hour (default 06:00). All plans.
- ▸Hourly monitors run at the top of every hour. Pro and Scale.
- ▸Monitor slots per plan: 1 / 5 / 25 / 100. Each check is one capture from your quota — a daily monitor uses ~30/month, an hourly one ~720/month.
How diffing works
Both captures are normalized to the same width, then compared pixel-by-pixel with a tolerance that ignores anti-aliasing and compression noise. The result is a percentage of changed pixels and a diff image — changed regions in warm yellow over the dimmed page — shown in the A / B / Diff viewer and attached to the check's archive entry.
The change threshold (0.1–10%, default 1.0%) decides what counts as "changed". Low values catch copy tweaks; higher values only fire on layout-level changes. Tune it per monitor with the slider.
Alerts
- ▸On change: email when a check crosses the threshold. You're alerted on the transition, then at most every 6 hours while the change persists — no inbox flooding.
- ▸On failure: one email after 3 consecutive failed checks (dead host, timeout). The schedule keeps running; an optional recovery email fires when it succeeds again.
- ▸One-click pause link in every alert — stop a noisy monitor straight from your inbox, no login.
- ▸Failed checks are not billed; a hard cap of 20 alert emails/day protects you from pathological pages.
Archive & retention
Every check's capture (and its diff image) is kept for your plan's retention window — 30 / 90 / 365 / 365 days — and browsable as a timeline on the monitor's page. Check history (dates, percentages, statuses) is kept indefinitely.