Page Change Monitor — Detect Website Changes, $0.001 a Check

Check web pages for text changes since the last run and get each one back as new, unchanged or changed, with the lines added and removed, for pricing pages, terms, docs and competitors watched on a schedule or by an agent. AI agents can call and pay for it through Apify's MCP server and agentic payments. It costs $0.001 per page checked, and a page that fails is never charged.

Example result

Example record for the minimal input under How to use it, as this Actor returned it on 2026-10-27 in a run of its production image; the record is kept unchanged with the release.

{
  "url": "https://docs.apify.com/",
  "ok": true,
  "finalUrl": "https://docs.apify.com/",
  "status": "new",
  "checkedAt": "2026-10-27T23:01:40Z",
  "previousCheckedAt": null,
  "contentHash": "5d5d1a744cfeef6686fc3575dba17e06440ad8921e36e6ae7490ad7a13efcfee",
  "added": [],
  "removed": []
}

How to use it

Start a run in Apify Console, by API or from an agent with an input like this one — it is the input Apify runs every day to test this Actor:

{"urls": ["https://docs.apify.com/"]}

Field	Type	Meaning
urls	array	Pages to check; one record each.
monitorName	string	Separate watch lists keep separate snapshots; runs with the same name compare with each other.
maxDiffLines	integer	At most this many added and removed lines are returned per page.

Events and prices

Event	Title	Charged when	FREE / BRONZE	SILVER	GOLD / PLATINUM / DIAMOND
page-checked	Page checked	One page fetched and compared with its last snapshot.	$0.001	$0.0009	$0.0008

Platform usage is not passed through. Apify's automatic actor-start event remains $0.00005 per started GB (one GB or less counts once). The synthetic dataset-item event is absent. Charge limits stop further paying work; unprocessed inputs receive uncharged errors. Completed readable pending events are settled on abort.

Worked cost example: ten successful page checked events cost $0.01 at list, plus actor start. Failures are not included in that count.

Call it from an agent

Through Apify's MCP server (https://mcp.apify.com) use call-actor:

{
  "actor": "hermeskd/page-change-monitor",
  "input": {
    "urls": [
      "https://docs.apify.com/"
    ]
  },
  "callOptions": {
    "maxTotalChargeUsd": 0.01,
    "timeout": 600
  },
  "waitSecs": 30
}

Then call get-dataset-items with the returned defaultDatasetId. Dedicated tool URL: https://mcp.apify.com?tools=hermeskd/page-change-monitor

Output fields

Field	Meaning
url	The input URL.
ok	True for a returned result; a failure is never charged.
finalUrl	The URL after redirects.
status	new (no earlier snapshot), unchanged or changed.
checkedAt	When this check ran, ISO 8601.
previousCheckedAt	When the compared snapshot was taken.
contentHash	SHA-256 of the page's normalized text.
added	Lines in the page now that were not there before.
removed	Lines that were there before and are gone now.
error	Failure, always uncharged.

Limits and run time

1–100 URLs a run. Each page is fetched once, up to 5 MB, under the 30-second per-request deadline; the page's visible text is compared, not its markup. Snapshots live only in your own Apify account, in a named key-value store page-change-monitor-<monitor>-<hash> the run creates there; nothing is kept in the developer's account, and deleting that store starts every page over as new.

Snapshots retain at most 2,000 characters per normalized line and 20,000 non-empty lines per page. Text beyond either limit is discarded before hashing and comparison, so changes confined to discarded text can be reported as unchanged.

The default run timeout is 600 seconds. Typical run time: not yet measured; written from the first deploy.

Errors

Code	Meaning
http_error	The source answered an unsuccessful HTTP status.
download_failed	The request or connection failed within its bounded deadline.
unsupported_content_type	The URL did not return an HTML or text page.
robots_disallowed	robots.txt forbids fetching the URL; no request was made to it.
blocked_host	The host is on the deny-list or resolves to a private or local address; no request was made.
too_large	The response exceeded the size cap.
timeout	The input did not finish within the run's time budget.
invalid_input	The run input passed the input schema but cannot be used; the message names the field.
internal_error	Unexpected failure; the message carries the error class.
charge_limit_reached	The run reached its maximum total charge; this input was not processed.

No failure record is charged. A run fails only when all input outcomes are Actor-side failures; caller errors and a mixture of caller/Actor failures do not fail the run.

Sources and terms

Only process content you have the right to process. URL fetches obey HermesBot robots-group selection, the shared deny-list, public-address checks on connections and redirects, honest identity, deadlines and rate limits. No caller credentials, cookies, CAPTCHA solving, residential proxies or evasion. Public pages the caller names are fetched under robots.txt; snapshots are stored only in the caller's own Apify storage. Process only content you have the right to process.

Not affiliated

This Actor is not affiliated with Apify or the owners of the pages it reads. Third-party names describe compatibility and source material.

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Changelog

• 1.0 (2026-10-27) — first release.