Diff Checker
Paste the original and the changed text to see exactly what was added, removed or modified, line by line with word-level highlights.
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How to use the Diff Checker
- Paste or drop the original text on the left and the changed text on the right.
- Review the differences in the side-by-side or unified view. Changed words are highlighted.
- Optionally ignore whitespace or letter case, then copy or download the result as a unified diff.
Features
- Accurate line diff (Myers algorithm) with word-level highlights
- Side-by-side and unified views
- Ignore whitespace and ignore case options
- Export as a standard unified .diff file
- Remembers your last comparison on this device
Frequently asked questions
How does the diff checker compare text?
It uses the Myers difference algorithm — the same approach used by Git — to find the smallest set of line insertions and deletions, then highlights the changed words inside modified lines.
Can I ignore whitespace changes?
Yes. Turn on Ignore whitespace to treat lines that differ only in spacing or indentation as unchanged. You can also ignore letter case.
Can I save the result?
Yes. Copy the result or download it as a .diff file in the standard unified format, which works with git apply and patch.
Is my data uploaded to a server?
No. Everything runs locally in your browser. Your input never leaves your device, so it is safe to use with private or proprietary data.