ChangeDetection.io tells you a page, or an element you picked, has changed; it is open source and can run on your own server. Crawlens watches the client sites you manage and, when something changes, produces a dated record you can show the client.
This is not a verdict on ChangeDetection.io; it follows who each product says it is for.
Both products look at whether a page changed. What they look at, what they call important and what they hand you are different. The ChangeDetection.io side is as described on its own site.
The pages of the client sites you manage, as a whole, in the same mobile browser and viewport on every scan. The image, the visible text and technical signals (noindex, robots.txt, canonical, forms, tracking tags, SSL and domain expiry) together.
The whole page, or elements you pick with CSS/xPath rules; JavaScript sites get a real Chrome browser.
It aligns the image for content that shifted, sets aside regions that change all the time such as rotating banners and ads, and scores what is left by visual impact, technical signal and where it sits on the page. You do not have to write rules to start.
With rules you write: trigger text, ignored text and selector filters.
A dated change record: the last good state, the new scan, the difference and its severity. Slack and email alerts; on agency plans, a report under your own brand that you can send to the client.
Alerts to more than 85 channels: Slack, Discord, Telegram, email and others.
Agencies seeing breakage on client sites after a deploy, an update or a plugin change before the client does, and explaining it to the client with evidence.
Price and restock tracking; in its own words, smart shopping and data journalism.
Rather than a table row about what Crawlens produces, here are two things you can open yourself.
Competitor prices read from their own pages on 2026-09-29. Our pricing page
| Product | Crawlens | ChangeDetection.io |
|---|---|---|
| Built for | Agencies that manage client sites: visual and technical change detection, a dated evidence record and a client-ready report. | Open-source web page change monitoring; its own site pitches it to smart shoppers, bargain hunters and data journalists. |
| Price |
|
Capacity from their own pricing pages; plan names are not translated. |
| Source | Our own price catalogue, the same source as the pricing page. | Read from the competitor's own pricing page. Read from ChangeDetection.io's own site. The open-source version can be self-hosted for free; the paid price is the hosted subscription. |
Competitor information here is summarised from their own public pages, not measured by us. Prices change; check the link before you decide. If something here is wrong, tell us and we will fix it.
The long version: read the ChangeDetection.io alternative article
Add your first site. When something changes, have the evidence ready before your client asks.
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