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Tutorial 2 min read

How to monitor a PDF on a website for changes

Paste the PDF’s address into a monitor and it compares the document page by page on every check, with an AI summary of what changed. Here is the setup, what you get, and what to do when the address changes with every version.

Alex Lead Product Designer
UpdatedOctober 17, 2026 Read time2 min AudienceProcurement, compliance and legal teams
A Monity task named GOV.UK · open consultations with the rule: A new consultation has been added to the list

To monitor a PDF on a website for changes, give a monitor the PDF’s address. monity.ai recognises the document, renders its pages and compares them on every check, so when a supplier replaces its price list or a regulator updates a form at the same link, you get an alert with an AI summary written from the document’s text and the pages before and after.

Step 1: Copy the PDF’s address

Open the PDF in your browser and copy the address, usually one ending in .pdf. PDFs that open in a viewer or sit embedded in a page work too.

Step 2: Create the task

Paste the address into a new task, or tell the assistant: “Watch https://www.irs.gov/pub/irs-pdf/fw9.pdf and tell me when the form changes”. Monity detects that it is a PDF and treats the document itself, not the browser’s viewer, as the page.

Add a Notify me when rule if only some changes matter, such as “a price in the table changes” or “the cancellation terms change”. Without a rule, any meaningful change alerts you.

What you get on each check

A Monity check of the IRS W-9 form: the rendered PDF pages with the changes and the check’s tabs
A check of a PDF task: the rendered pages, compared with the previous version.
  • An alert with an AI summary based on the document’s text.
  • The pages before and after, with the differences highlighted, and a PDF Diff tab that lists the metadata and the changes page by page.
  • Every version kept in the task’s history, so you can see when a clause or a price changed.

When the address changes with every version

Many sites replace a PDF at the same link when they update it, and that is exactly what a PDF task catches. If the site publishes each version at a new address instead, watch the page that links to the PDFs. Monity reads the list of documents on that page, and the alert names the new one.

PDFs behind a login

Supplier portals and member areas often keep their PDFs behind a sign-in. Sign in once in the live browser and every check runs signed in. See how to monitor a page behind a login.

Related: getting an alert when a web page changes, the complete guide to monitoring a website for changes, the PDF task in the docs and PDF and document monitoring.

FAQ

Questions people ask

Which documents can monity.ai monitor?

PDFs, at an address or embedded in a page. Word and Excel files are not compared.

Can I be told only when a specific number changes?

Yes. Write it in the rule, such as “the unit price of item 4 changes”, and other edits stay quiet.

Do I have to download the PDF?

No. Monity loads the document at its address on every check.

Can I compare two PDFs right now, without setting up monitoring?

Yes. The free PDF diff tool compares two versions in your browser.

Written by

Alex

Alex leads product design at Monity, where the goal is simple: make powerful website monitoring feel effortless. From the plain-English setup flow to the way every alert is laid out, Alex.'s work is about removing friction so anyone — not just technical teams — can watch the pages that matter. Here, Alex writes about product design, usability, and the craft of making complex tools feel calm and obvious.

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