Website change detection that tells you what changed, not that something did
A change monitor takes a baseline of a page, then re-checks it on your schedule and compares what it finds. It looks at both the text and the pixels, ignores the parts of a page that churn on their own, and alerts you only when the difference is big enough to matter. You get a before and after.
14 days, no card required.
What counts as a change?
Two signals, either of which can trip an alert. The text of the watched area changed enough to be meaningful rather than a stray character. Or the rendered pixels differ by more than a small threshold, which catches a layout or styling break that the text alone would miss.
Small wording tweaks and single-character edits do not trip it. That threshold is the difference between a monitor you keep and one you mute in a week.
Can you watch part of a page instead of all of it?
Yes, and this is usually what you want. Pick the region in a live preview of the page and the monitor watches only that: a price, a banner, a stock message, a headline. Everything else can change freely without alerting you.
Simrix Monitor stores both the element you picked and where it sat on the page. If the site's markup changes underneath you, the monitor falls back to the saved position rather than going silent, which is the usual way this kind of monitoring quietly stops working.
What about ads and cookie banners?
They are handled before the comparison happens. Ad containers are hidden and cookie prompts are dismissed before the page is captured, and the monitor remembers which dismissal worked on which site so later checks get cleaner captures.
Without that, a rotating ad slot alone would report a change on every single check.
How sensitive can you make it?
Three settings, chosen per monitor.
| Sensitivity | What it compares | Good for |
|---|---|---|
| Fast | Text only, unless the text has moved | Pages where wording is what matters |
| Balanced | Text and pixels | Most pages |
| Focused | Always compares the rendered image | Layout, styling and visual breakage |
What do you get when something changes?
A before-and-after you can drag between, a highlighted image of exactly which pixels differ, the text that was added and removed, and a plain-English headline describing the change along with how significant it looks.
What does it cost?
| Plan | Monitors | Fastest check | Sites | Per month |
|---|---|---|---|---|
| Free | 2 | 6 hr | 1 | Free |
| Starter | 10 | 30 min | 3 | $49 |
| Growth | 50 | 15 min | 10 | $149 |
| Pro | 150 | 5 min | 25 | $349 |
| Agency | 500 | 1 min | 75 | Talk to us |
Annual billing is 2 months free. See full pricing or start a 14-day free trial, no card required.
14 days, no card required.
Frequently asked questions
Will the first check tell me something changed?
No. The first check stores the baseline, so there is nothing to compare against yet. The check after it is the first that can report a change.
Can I watch a page on a site I don't own?
Yes, as long as it is publicly reachable. That is how competitor watching works. Private network addresses are blocked. A region that looks like it holds passwords, payment fields or personal data is flagged for review rather than blocked.
Will I get an alert every time an ad rotates?
No. Ad containers are hidden and cookie banners dismissed before the page is captured, and small text differences fall under the threshold.
How is this different from a workflow monitor?
A change monitor compares a page against its own past. A workflow monitor drives a journey and asserts a result. Change monitors are for watching; workflow monitors are for proving something still works.
How long do the before and after images last?
Seven days. The record of each check and what it found is kept, but the images behind older checks are removed.
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