A revision tracker for any PDF document

Don't read the new version cover to cover trying to figure out what your counterparty changed. Run both versions through PDFverifier and the difference list arrives in 30 seconds.

Manual revision review vs. automatic diff

If your workflow currently looks like "open both PDFs on two monitors, scroll, look for highlighting" — you're losing hours per project and probably missing changes. Here's the realistic comparison:

What you do	Manual review	PDFverifier
Time for a 20-page revision	45-90 min focused	~1 min including review
Detection of small graphic changes	Easily missed	Pixel-level — never missed
Tracking which changes you've reviewed	Notes on paper or in head	Each change has explicit accept/reject state
Producing a record of what changed	Separate write-up needed	Annotated PDF exported in one click
Sharing the result with your team	Send your own notes	Single annotated PDF, self-documenting

When to reach for it

PDFverifier earns its keep wherever the cost of missing a revision change is meaningful:

Contract redlines — confirm exactly which clauses your counterparty edited between drafts before signing
Specification updates — catch material or tolerance changes in technical specs that could affect procurement
Drawing revisions — see every CAD change before issuing instructions to site
Report drafts — track edits during internal review cycles
Policy documents — see what compliance changed between annual updates
Tender responses — review what changed between addenda

Why pixel-level rather than text-level

Most "PDF compare" tools that came out of the 2010s extract text from each PDF and compare strings. That works for clean text documents, but breaks on three common cases:

Scanned documents

OCR is imperfect and produces different strings on different scans of the same page — text-diff floods you with phantom changes that don't exist.

Graphical content

Anything that's actually drawn — diagrams, signatures, stamps, charts — has no text to extract and is simply ignored by text-diff.

Layout changes

A paragraph that moved from page 3 to page 4 reads identically as text but is a real visual change. Text-diff misses it; pixel-diff catches it.

PDFverifier renders both PDFs to high-resolution images and compares the pixels. That's slower than text-diff but catches everything that's actually visually different — which is what "changed" actually means to a human reviewer.

Frequently asked questions

Does it work on password-protected PDFs?

The PDFs need to be readable when uploaded. Remove the password first, or open and re-export without it. We don't store the unlocked file beyond your session.

How is "track changes" different from "diff"?

"Track changes" usually means changes recorded by the editing tool (Word, Acrobat) as the user edits. PDFverifier doesn't need that — it derives changes from the final PDFs themselves, so it works even when the original software didn't record anything.

Will it tell me who made each change?

No. PDFverifier only knows what changed, not who or when. For that you'd need the source document's revision history. PDFverifier complements that — it tells you what actually ended up in the PDF, which can differ from what was tracked.

Can I compare a PDF against an earlier version stored elsewhere?

Yes — you just need both as PDF files. Pull the old version from your DMS or archive, drop in the current one, run the comparison.

How long are my revisions stored?

7 days on the free tier, 30 days on paid sessions. Pro users get 90 days of session history so you can come back to a comparison later in the project.

Start tracking revisions properly

You can run a revision comparison free — no installation, no plugin, no sign-up needed for previews.

Open PDFverifier →