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.
V1
V2
Original (v1)
Revised (v2)
Compared locally — your files never leave your device.
Processed locally — never uploaded
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// Benefits
Compare an original and a revised PDF and see every text change marked up — no need to read both side by side.
Added text is highlighted and removed text is struck through in one continuous read, so you never miss a quiet wording change.
A sentence-level diff scans through hundreds of pages and surfaces only what actually changed between the two versions.
See at a glance how many passages were added versus removed before you read a single line of the markup.
// Workflow
For the moment two versions of a contract, policy, or report land on your desk and you have to know exactly what moved.
Upload the original PDF and the revised PDF you want to compare.
Run the comparison to red-line every added and removed passage.
Read the marked-up result and download or share what changed.
// Recommended reading
Related tools and guides for reviewing and finalizing PDFs.
Upload the original (v1) and the revised (v2) PDF, then click Compare versions. DockDocs lines up the text and shows a marked-up view — added text is highlighted in green, removed text is struck through in red. This is the same redline view used in contract negotiation and legal document review to track what changed between versions.
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.
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.
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.
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.
Yes — comparing versions is completely free, with no sign-up and no limit on the number of comparisons.
Yes. Upload the earlier version and the revised version, and DockDocs shows a full redline of the contract text — added clauses highlighted in green, removed text struck through in red, sentence by sentence. It shows all textual changes; for scanned contracts without a text layer, run OCR first to make the text readable.
Redlining and redacting are opposite operations. Redlining marks proposed changes during negotiation — additions highlighted, deletions struck through — so both parties see exactly what's changing. Redacting permanently removes sensitive text before sharing a document, blacking out names, amounts, or confidential clauses so the recipient sees only what you intend to disclose. If you're negotiating, you redline. If you're sharing but need to hide information first, you redact. DockDocs has both: this tool compares PDF versions and shows what changed; the Redact PDF tool blacks out sensitive text before sharing.
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.