PDF Redline Tool for Contracts and Documents

Compare two versions of a contract, specification, or technical document. DrawDiff overlays them visually and extracts word-level text differences — all in your browser, without sending your documents to any server.

    Confidentiality guaranteed by architecture. DrawDiff has no server. Your PDFs are processed entirely in your browser and never transmitted anywhere. This is not a privacy policy promise — it is a technical fact.
  

Two Ways to Compare Documents

Visual Overlay

Pixel-accurate overlay of both PDFs
Green = removed content, Red = added content
Catches formatting changes, layout shifts, graphic updates
Works even if the document has no extractable text (scanned)
Export as JPG or PDF for review records

Text Diff

Shift+drag or click Ⓣ Text Compare to select a region
Extracts text from both PDFs in the selected area
Word-level diff: green = added words, red = removed words
Precise tracking of clause-level changes
Works with any PDF that has selectable text

Common Document Comparison Scenarios

Contract negotiations — track changes between counterparty redlines and your version
Specification revisions — identify every changed requirement between spec issues
Subcontract agreements — compare a subcontractor's marked-up version against your issued version
NDA and confidentiality agreements — review changes to sensitive documents without uploading them
Regulatory submissions — verify that a revised submission matches the approved version except for the intended changes
Purchase orders and schedules — catch unexpected changes in revised commercial documents

Why Not Just Use Track Changes?

Track Changes works when both parties use the same Word document workflow. In practice, contracts often arrive as PDFs — printed-to-PDF, signed, scanned, or issued from a system that generates PDFs directly. DrawDiff compares any two PDFs regardless of how they were created.

It also catches things Track Changes misses: formatting shifts, page layout changes, moved tables, and any visual change that doesn't show up as a text edit.

Limitations to Know

Text extraction requires selectable text. The Text Compare feature works with PDFs that contain selectable text — standard PDFs generated from word processors or CAD tools. Scanned documents (image-only PDFs) show changes visually in the overlay but text extraction will return nothing. OCR support is planned for a future release.

Privacy and Confidentiality

DrawDiff is built specifically for sensitive documents. The entire application runs as a static website — there is no server component, no API, and no mechanism by which your documents could be transmitted or stored externally. Google Analytics collects anonymous usage events (page loads, button clicks) but never any document content. See the Privacy Policy for full details.

For organisations with strict document handling requirements, DrawDiff can be bookmarked and used entirely offline once the page is loaded.

Compare your documents now — free, private, no account required.

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