Diff Checker
Paste two versions of any text side by side and click Compare to see exactly what changed — added lines in green, removed lines in red.
How to diff Checker
- Paste the original text in the left panel.
- Paste the modified text in the right panel.
- Click "Compare" to generate the diff.
- Review additions (green +) and deletions (red −) in the output.
Private by design — text comparison runs entirely in your browser. Your content is never uploaded to a server.
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Frequently asked questions
What diff algorithm is used?
This tool uses the diffLines algorithm from the 'diff' npm package, which computes a line-by-line diff similar to the Unix diff command.
Can I compare code files?
Yes — paste any plain text content including source code, JSON, configuration files, or prose. The diff is purely text-based.
Does it support word-level or character-level diffs?
Currently the tool shows line-level diffs. Word and character-level diffing may be added in a future update.
Is there a size limit?
There is no hard limit — the diff runs in your browser's JavaScript engine. Very large files (hundreds of thousands of lines) may be slow to compute.