Website Change Monitor: Diff Any Page

Website change detection for any page: find out exactly what changed — the lines that were added and the lines that were removed, not just "something moved".

A competitor's pricing page. A supplier's terms. A careers page. A status page. A government notice. Anything with a URL.

How this website changes monitor works

The first run records a baseline and returns nothing — you are not charged for it. Every run after that compares the page and returns a row only when it actually changed.

Noise is filtered out for you: clock times, ISO timestamps and CSRF tokens are ignored automatically, and you can add your own patterns for visit counters or rotating banners.

How to monitor a website for changes

Field	What it does
urls	Pages to watch
selector	Watch only part of the page, e.g. .pricing-table
ignorePatterns	Regular expressions for text that always changes
alertKeywords	Only report when a word like "price" or "discontinued" appears in the change
minChangedCharacters	Ignore tiny edits
reportFirstRun	Return the baseline too, if you want it

What the page change output looks like

One row per changed page:

{
  "url": "https://httpbin.org/uuid",
  "changeType": "baseline",
  "title": null,
  "contentLength": 51,
  "checkedAt": "2026-09-21T11:07:20.774Z"
}

A page that starts returning 404 or 410 is reported as changeType: "unavailable" — a removed product or a pulled job posting is a change worth knowing about.

How fast is it and what does it cost?

3 pages take about 3 seconds. Unchanged pages produce no rows, so a daily watch on 50 pages costs almost nothing until something happens.

Ready-made examples

Open one, change the fields, press Start — nothing to configure:

• Monitor a competitor pricing page for changes
• Website change detection for any page

Frequently asked questions

Do I need an API key or a login?

No. Paste your input, press Start. There is nothing to connect and no account on the target site to create.

How do I export the results?

Every run produces a dataset you can download as JSON, CSV, Excel, XML or HTML, or read through the Apify API from your own code. You can also connect it to Make, Zapier or n8n.

Can I run this on a schedule?

Yes. Apify schedules run it every hour, day or week without you being there. That is the whole point of this Actor: a scheduled run returns only the pages that changed.

Can I call it from Python or JavaScript?

Yes — the Apify API runs any Actor and returns the dataset, and the official Python and JavaScript clients wrap it in a few lines. AI agents can call it too, through Apify's MCP server.

What does it cost?

You pay per result, not per hour. Filters are applied before anything is charged, so narrowing the input directly lowers the bill. Pages that cannot be read are reported in the log and never charged.

Is this data public?

Everything collected here is what any web page shows to anyone without logging in. Check the target site's terms and the rules that apply to you before using the data commercially.

Related scrapers

• Price & Stock Monitor for Any Shop — prices specifically
• Structured Data Extractor — what a page declares about itself
• Website to Markdown for AI & RAG — the full text, cleaned up