Compare versions

Upload an original and a revised PDF to see exactly what changed — added text is highlighted, removed text is struck through. Everything runs in your browser.

Original (v1)

Revised (v2)

Compared locally — your files never leave your device.

// Benefits

Why redline PDFs in your browser

Compare an original and a revised PDF and see every text change marked up — no need to read both side by side.

Every edit, marked in place

Added text is highlighted and removed text is struck through in one continuous read, so you never miss a quiet wording change.

Built for long documents

A sentence-level diff scans through hundreds of pages and surfaces only what actually changed between the two versions.

A clear added/removed tally

See at a glance how many passages were added versus removed before you read a single line of the markup.

// Workflow

How redlining fits your review work

For the moment two versions of a contract, policy, or report land on your desk and you have to know exactly what moved.

  1. 1

    Upload the original PDF and the revised PDF you want to compare.

  2. 2

    Run the comparison to red-line every added and removed passage.

  3. 3

    Read the marked-up result and download or share what changed.

// Recommended reading

More ways to work with documents

Related tools and guides for reviewing and finalizing PDFs.

Compare PDF versions (redline) — FAQ

How do I compare two PDF versions?

Upload the original (v1) and the revised (v2) PDF, then click Compare versions. DockDocs lines up the text and shows a single marked-up view — added text is highlighted in green, removed text is struck through in red, like track changes.

Are my files uploaded anywhere?

No. This is a client-side tool: the text is extracted and compared entirely in your browser, so your files never leave your device. Nothing is sent to a server.

Does it catch reworded sentences?

It compares sentence by sentence, so it marks which sentences were added and which were removed. A small reword shows up as one deletion plus one addition rather than a word-level change inside the sentence.

What does it actually compare — does it check formatting or images?

Only the extracted text. Fonts, layout, colors, images and tables aren't part of the comparison, and scanned PDFs with no real text layer won't produce useful results. If it reports no textual changes, the wording is identical even if the look changed.

How large can the documents be?

The whole comparison runs in your browser, so it's tuned for documents up to a few thousand sentences (it caps at 2,500 sentences per file). Very long contracts or books may be truncated or run slowly.

Is it free?

Yes — comparing versions is completely free, with no sign-up and no limit on the number of comparisons.

Don't take our word for it — verify it

This tool runs entirely in your browser. Your file never leaves your device — it isn't uploaded to any server.

Check for yourself: open your browser's developer tools (F12, or right-click → Inspect) → the Network tab → then run this tool. You won't see your file uploaded anywhere, because the work happens locally on your device.