Website Change Monitor

Monitor web pages for content changes and receive structured diff reports. Ideal for:

• Competitor monitoring — track changes on competitor landing pages, pricing, or feature listings.
• Policy change detection — get alerted when terms of service, privacy policies, or regulatory pages update.
• Price tracking — detect price changes on product pages.
• News & blog monitoring — know when new articles or updates are published.

How it works

1. Set the URL you want to monitor (and optionally a CSS selector to scope checking).
2. On each run, the Actor fetches the page, extracts readable text, and compares it against the previous run's content (stored automatically in the Actor's key-value store).
3. A structured diff report is saved to the default dataset with:
   • changed — boolean flag
   • diff — unified diff string (+ lines added, - lines removed)
   • added / removed — lists of changed lines
   • checked_at — timestamp
   • content_hash — SHA256 for quick cache-busting checks
4. Optionally, configure a webhook URL to receive POST notifications only when a change is detected.

Input

Field	Type	Required	Description
url	string	✅	Full URL of the page to monitor
selector	string	❌	CSS selector to limit monitoring to a specific element
webhook_url	string	❌	URL to POST change notifications to
previous_content	string	❌	Previous content override (falls back to stored value)

Output

Each run produces one dataset entry with the following structure:

{
  "changed": true,
  "diff": "+ New pricing: $49/mo\n- Old pricing: $39/mo",
  "added": ["New pricing: $49/mo"],
  "removed": ["Old pricing: $39/mo"],
  "url": "https://example.com/pricing",
  "checked_at": "2026-05-29T12:00:00+00:00",
  "content_hash": "a1b2c3d4e5f6..."
}

Pricing

• $0.01 per check run — webhook notifications included at no extra cost.
• No hidden fees, no per-result surcharges.

Example usage

Basic monitoring

{
  "url": "https://example.com/pricing"
}

Scoped monitoring + webhook

{
  "url": "https://example.com/pricing",
  "selector": "#pricing-table",
  "webhook_url": "https://hooks.slack.com/services/xxx/yyy/zzz"
}

Storage

• Previous content is automatically persisted in the Actor's key-value store under the key last_content.
• Diff results are pushed to the default dataset and can be exported as JSON, CSV, Excel, etc.
• The content hash enables external systems to quickly check if content changed without re-reading the full diff.

Development

# Install dependencies
pip install -r requirements.txt

# Run locally (requires Apify token)
python -m src