What Is Contract Redline Tool?
Contract Redline Tool compares two versions of a contract or legal document and highlights every change — additions, deletions, and modifications. It’s the standard workflow for negotiating agreements, reviewing edits from opposing counsel, and tracking revisions across contract drafts.
How to Use This Tool
Upload the original and the revised version (PDF, DOCX, TXT or MD), or paste the text into the box under each slot. Choose Word to see changed words inside sentences, or Line to see which lines changed. The redline shows insertions in green and deletions in red with strikethrough, with counts of words or lines added, removed and unchanged, and you can export it as an HTML file. The comparison is of the text only: changes to formatting, numbering styles or layout are not shown. All comparison happens in your browser — your contract text never leaves your device.
Why Use Contract Redline Tool?
Professional redlining tools are built into expensive legal software suites. This tool provides a text redline for free, with the critical advantage that sensitive contract language is never uploaded to any server. It’s ideal for freelancers, small businesses, and anyone reviewing agreement changes. For a detailed walkthrough, see our step-by-step guide.
Frequently Asked Questions
How is this different from Word's Track Changes?+
Word's Track Changes requires both parties to be using Word and to have kept change tracking enabled throughout every edit. If a collaborator edits without it on, accepts all changes, or sends you a fresh PDF, the audit trail is lost. Contract Redline works on final artifacts — drop in any two versions of a contract (even as PDFs after a round trip through signing software) and we reconstruct the redline from the actual text.
Does it work on PDFs or only Word files?+
Both, plus TXT and Markdown files or pasted text, and you can mix them: compare a PDF against a Word document, or two PDFs. Text is extracted with pdf.js for PDFs (keeping its line breaks) and mammoth for DOCX, then compared. Because PDFs and Word files break lines differently, word mode is the better choice when the two versions are in different formats.
Will it detect moved paragraphs?+
No. A moved paragraph shows as a deletion where it was and an insertion where it now is, in both word and line mode. When a redline shows the same text removed in one place and added in another, that is usually a move; read both spots side by side to confirm nothing changed inside it.
Is my contract uploaded to a server?+
No. Both files are parsed locally in your browser. pdf.js handles PDF text extraction entirely client-side; mammoth does the same for DOCX; the diff runs in-browser JavaScript. No uploads, no server side processing, no record kept of your document contents. This matters especially for contracts containing sensitive commercial terms.
Does it handle scanned contracts (images of text)?+
Not directly — the tool extracts the PDF's text layer, which scanned PDFs don't have. First run your scanned PDF through our PDF OCR tool to generate a searchable text layer, then feed the OCR'd result into Contract Redline. Note that OCR errors can introduce false differences between the two compared files, so review the OCR output before comparing.
Can I export the redline?+
Yes. Export as an HTML file that preserves the red/green highlighting — you can open it in a browser, email it, print to PDF, or share as-is. The output is styled for screen and print, and keeps the insertions/deletions/unchanged formatting so a reviewer can scan through quickly.
Does the tool replace having a lawyer review the contract?+
No. The tool shows what changed in the text between two versions; it does not interpret the changes or flag risky clauses. For any contract over a meaningful amount of money, any contract that grants rights to your IP or your data, or any contract that limits your ability to compete or work, have a licensed attorney in your jurisdiction review the final text before signing.
Are the contracts I paste analyzed in my browser or sent to a server?+
In your browser. Pasted text and uploaded files are read and compared locally, and nothing is sent to a server or an AI service. This matters because contracts often contain confidential commercial terms, party names and pricing. The only network requests are for the page itself and its libraries (pdf.js, mammoth and React).
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