Compares two input texts side-by-side, highlighting inserted, deleted, and changed lines with distinct background colors. Code never leaves your device — formatting and validation run locally in your browser.
Runs on diff-match-patch
Content reviewed October 2026 · About Toolzum
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Insertions (new lines added), deletions (lines removed), and modifications (changed lines) are each highlighted with distinct background colors so you can spot every difference at a glance.
There's no hard limit. Very large texts (100KB+) may take a moment to compare, but the diff-match-patch algorithm handles substantial inputs efficiently.
Yes. Paste any text — code, config files, documentation, or plain text. The tool compares line-by-line and highlights exactly what changed between the two versions.
Yes. After the initial page load, the comparison runs entirely in your browser using the diff-match-patch library. No data is sent to any server.
The highlighted comparison is displayed visually. You can select and copy the text from either panel, or take a screenshot of the side-by-side view.
A unified-style text where every line is prefixed + for additions (op 1), - for deletions (op -1) or a space for unchanged context (op 0), split per newline. It downloads as diff.txt from the Comparison Output toolbar.
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