What is Document Comparison?

The Document Comparison tool highlights every addition, deletion, and change between two text documents. Paste your original and revised text to get a clear side-by-side or unified diff. It works for contracts, code, or any written content you need to check.

Comparison runs the Myers diff algorithm, the same engine behind git diff. Pick line granularity for paragraphs and code blocks, word granularity when a single sentence has been edited, or character granularity to catch a one-letter typo or a stray punctuation mark. The result shows up either side-by-side or as a unified inline diff with additions in green, deletions in red. A swap button flips your two inputs, you can upload a text file straight into either panel, and you can export the diff as plain text or as a styled HTML report ready to share with a reviewer.

How to use

1. Paste your original text in the left panel and the revised version in the right panel.
2. Click Compare to see differences highlighted in color: green for additions, red for deletions, and yellow for modifications.
3. Switch between side-by-side and unified views. Copy the diff summary or export it as an HTML report.

When to use

• Reviewing two contract revisions and spotting clauses that were silently reworded.
• Comparing a code patch to the original file when GitHub isn't an option.
• Catching what changed in a marketing brief that came back from the legal team.

Result

A legal team pastes two contract drafts to instantly spot that clause 4.2 was reworded and section 7 was entirely removed — saving hours of manual reading.

FAQ

What's the difference between line, word, and character granularity?

Line mode treats each newline as a unit and shows whole rows added or removed — fastest for code and tables. Word mode breaks the text into words and highlights the smallest changed phrase, which is clearer for prose edits. Character mode goes finer still and marks individual changed letters, so a single typo or a swapped comma stands out. Character results are shown in the unified inline view since a per-letter side-by-side layout would be unreadable.

Will the comparison ignore whitespace differences?

It can, if you want it to. Turn on "Ignore whitespace" and leading or trailing spaces and tabs stop counting as a difference, which is handy when one file was reformatted or re-indented. There's also an "Ignore case" toggle so capitalisation changes don't show up as edits. Both are off by default, so a normal comparison still treats every space and letter exactly as written.

Can I diff long documents like a 50-page contract?

Yes. Long documents stay responsive because the "Collapse unchanged" option (on by default) hides the matching runs and only renders the lines around each change, so a 50-page contract with a few edits draws just a handful of rows. Past roughly 10,000 lines that are mostly different, things still get heavy since every changed segment has to be drawn — for cases like that, split the text by chapter or section and compare in chunks, or reach for a desktop tool that streams the result.

What does the exported HTML report look like?

A single, self-contained HTML file with inline CSS, a small header showing addition and deletion counts, and the full diff with coloured backgrounds. It opens in any browser without dependencies, so you can email it or attach it to a ticket without losing the formatting.

Is the text uploaded anywhere when I click Compare?

No. Both panels and the diff calculation stay in your tab. The library running the comparison is loaded once with the page and runs against the text you typed. Closing the tab clears the content.

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