Paste two versions of a text or markdown file and see every added, removed, and changed line. Everything runs in your browser — nothing is uploaded.
Put the original text on the left and the changed version on the right.
The comparison updates as you type — green lines were added, red lines were removed.
Copy the unified diff with +/− markers to share in a review, issue, or commit message.
A real longest-common-subsequence diff — the same idea Git uses — so unchanged lines stay matched even when text moves around.
Compare README revisions, docs, notes, or any plain text. Whitespace is preserved exactly as written.
The comparison runs entirely in your browser. Nothing you paste is uploaded, stored, or logged.
Live results as you type, line numbers for both versions, added/removed counts, and one-click copy of the unified diff. No signup.
knowdust is a markdown notebook that keeps a version of every save automatically — open any note's history and see a diff like this for any day you wrote, without copying anything anywhere.
Start writing freeIt uses a longest-common-subsequence algorithm on lines — the same family of algorithm Git and code-review tools use. Matching lines are aligned, and everything else is shown as added or removed.
No. The comparison runs entirely in your browser with JavaScript. Nothing you paste leaves your device.
Yes — markdown is plain text, so it diffs cleanly. Paste the two versions of your README, docs page, or note and the changed lines are highlighted.
The green + count is lines that exist only in the changed version; the red − count is lines that were in the original but are gone. A modified line counts as one removal plus one addition.
Very large inputs (roughly beyond a few thousand changed lines) switch to a simplified comparison so your browser stays responsive. Typical documents, notes, and config files are handled precisely.
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