Getting started

What it does

You give it two versions of the same document — the older ("original") and the newer ("revised") — and it produces a marked-up copy showing every change. Three kinds of output exist:

Word redline with tracked changes (.docx) — real Word revisions; the recipient reviews them with Word's own accept/reject tools. This is the filing artifact: accepting all changes reproduces the revised document, rejecting all restores the original — and the tool verifies that on every run.
Word redline with baked colors (.docx) — the same changes flattened into fixed colors (insertions underlined, deletions struck through). Looks identical in every viewer, ideal for PDF conversion, but can no longer be accepted/rejected.
Excel colored review copy (.xlsx, spreadsheet pairs only) — the actual revised workbook with colored fills: green = inserted, amber = changed (previous value in a cell comment), red struck-through = deleted rows spliced back. For reviewers who live in Excel; not the filing artifact.

inserted
changed
deleted
verified

Supported files

Word family: .docx, .docm
Excel: .xlsx
Both files of a pair must be the same kind — you can't compare a workbook against a Word document.
Excel pairs can produce either a Word redline (the worksheets' print areas are laid out as Word tables mirroring the printed rate pages) or the colored review copy.

Your first comparison

Open the app at your deployment's address (for example https://redline.your-domain.com).
Drop the older file on the left tile, the newer on the right (or click Browse device).
Pick an output under 2 · Output — sensible defaults are pre-selected (Word colored for Word pairs, Excel copy for Excel pairs).
Click Compare. The result downloads automatically; a green box confirms it, with a ✔ Verified badge when the round-trip check passed.
Open the download. The first page (Word) or the Legend sheet (Excel) is the comparison report: every change listed and clickable, summary statistics, and the certificate.

To run another comparison, just change anything — a file, a version, an option. The previous result clears automatically; no page refresh needed.

When something can't be redlined faithfully

The tool never hides a limitation Anything it couldn't render faithfully (pictures dropped from a print area, content outside the compared scope that differs, a formatting-only change) appears as a warning — in the yellow box on screen and on the report page. A warning never blocks the output; it tells you where to look manually.