Website Change Monitor & Alerts

A production-ready Apify Actor for tracking meaningful changes on public websites without babysitting pages or drowning in noise.

Buyer outcome: get a clear, structured signal when a competitor page, policy document, listing, help article, or monitored content region changes.

Why this product exists

The best buyers for this Actor are people who need alerts they can trust:

• founders watching competitors
• operators tracking pricing or policy pages
• traders monitoring listings, inventory, or market-adjacent pages
• recruiters and analysts watching job boards or directories
• compliance teams watching terms, help docs, and policy updates

What it does

• monitors a full page or a specific CSS selector
• strips noisy sections before comparing snapshots
• keeps state in a persistent key-value store between runs
• detects both raw and meaningful changes
• supports webhook notifications on meaningful changes
• works locally and on Apify Cloud

Core features

Feature	What it solves
URL monitoring	Track any public page
CSS selector support	Focus on the part that matters
Ignore selectors	Remove cookie banners, promos, ads, and other noise
Change threshold	Avoid false positives from tiny edits
Persistent state	Compare against the last run, not just the current run
Webhook alerts	Forward important changes to your own system

Input example

{
  "url": "https://example.com",
  "selector": "main",
  "ignore_selectors": ".cookie-banner,.ads,.promo",
  "min_change_ratio": 0.05,
  "webhook_url": "https://your-endpoint.example/webhook"
}

Input reference

Field	Required	Description
url	yes	Page to monitor
selector	no	CSS selector to monitor a specific region
ignore_selectors	no	Comma-separated CSS selectors removed before hashing
min_change_ratio	no	Minimum normalized difference before a change counts as meaningful
webhook_url	no	Endpoint that receives the JSON result on meaningful change
state_key	no	Custom storage grouping key for shared or split snapshots
user_agent	no	Custom HTTP user agent
timeout_seconds	no	Request timeout in seconds

Output

Each run writes one dataset item with:

Field	Meaning
status	initial_snapshot, unchanged, minor_change, or changed
raw_changed	Whether the content hash changed
significant_change	Whether the change crossed the threshold
change_ratio	Normalized difference score
current_hash / previous_hash	Stable snapshot hashes
current_excerpt / previous_excerpt	Short previews for quick review
webhook_sent	Whether a webhook was successfully sent
webhook_error	Error text if webhook delivery failed

How the detection works

1. Fetch the page with a normal browser-like user agent.
2. Remove script/style and any selectors you mark as noisy.
3. Extract either the selected region or the full body text.
4. Compare against the previous stored snapshot.
5. Mark the result as:
   • initial_snapshot
   • unchanged
   • minor_change
   • changed
6. Optionally send the full JSON payload to your webhook when the change is meaningful.

State model

This Actor stores snapshots in a named key-value store, not the run-scoped default store. That means the previous snapshot survives across Apify Cloud runs and production use.

If you need separate monitors for the same URL, set different state_key values. If you want multiple monitors to share state intentionally, reuse the same state_key.

Good buyer stories

This Actor sells best when positioned for real operational outcomes:

• “Track competitor pricing changes”
• “Watch policy pages and get notified instantly”
• “Monitor product pages for restocks and content changes”
• “Track directory or job board listings without manual checks”
• “Send webhooks to Slack, Discord, Make, Zapier, or your backend”

Local development

$apify run

Deploy

apify login --token <your-token>
apify push

Notes

• The Actor is intentionally lightweight and fast.
• It is designed for clear, explainable alerts instead of noisy scraping.
• Webhook delivery is optional, so it works fine as a pure monitoring tool too.