Web Page Change Detector — Watch a Section by ID or Class

Know when a web page changes — the whole page, or just one section such as a pricing table (#pricing) or a terms block (.legal-text). Each run fetches the page, hashes the text with SHA-256 and compares it with the hash saved by the previous run for the same monitorKey.

Choose this Actor when you want a cheap yes/no "did it change?" signal on a schedule for server-rendered pages — vendor pricing pages, policy pages, public notices, documentation — and you will trigger your own alert or workflow when changed is true.

Not the right fit when the content is rendered by JavaScript in the browser (this Actor does a plain HTTP fetch), when you need a line-by-line diff of what changed, or when you need complex CSS selectors (only #id and .class are supported; anything else checks the full page text).

Use cases

• Competitor pricing pages — know the day a plan or price block changes.
• Terms, privacy and policy pages — compliance teams tracking edits.
• Public notices and tender pages — detect a new posting on a static page.
• Documentation and changelogs — trigger a review when a section changes.

How to set it up

1. Enter the url and a stable monitorKey (e.g. acme-pricing-page). Keep the key the same forever for this page — it is how the Actor finds the previous hash.
2. Optional: cssSelector #pricing or .plans to ignore the rest of the page (dates, banners).
3. Run once — the first run stores a baseline (first_run: true, changed: false).
4. Save it as a task and add a schedule (e.g. daily).
5. Add an integration on the task (webhook, Slack, email, Make, Zapier, n8n) and filter for changed: true.

One run checks one page. For several pages, create one task per page with its own monitorKey.

Input example

{
  "url": "https://example.com/",
  "monitorKey": "example-com-home",
  "cssSelector": ""
}

Output (one row per run)

{
  "url": "https://example.com/",
  "monitor_key": "example-com-home",
  "sha256": "…64 hex characters…",
  "changed": false,
  "first_run": true
}

Pricing

Example: one page checked daily for 30 days with 2 changes = 30 × $0.01 + 2 × $0.05 = $0.40. Platform usage is included.

FAQ

Why did the first run say changed: false? There was no stored hash yet; the first run saves the baseline.

A timestamp or counter on the page triggers changes every run. Narrow the check with cssSelector to the #id or .class that holds the content you care about.

Does it work on JavaScript-heavy sites? Only if the text you watch is present in the HTML the server returns. Content injected by browser JavaScript is not seen.

Does it tell me what changed? No — it tells you that it changed. Open the page, or pair it with a scraper for the details.

Does it send alerts? Use Apify integrations on the task (webhook, Slack, email, Zapier, Make, n8n).

Need a feature? Open an issue on the Issues tab — include your run ID.