Diff Checker
Compare two texts and highlight exactly what was added or removed.
How it works
Paste two versions of a text to see exactly what changed — added text in green, removed in red. Compare by line, word or character. Great for contracts, config files, code and drafts.
🔒 Processed entirely in your browser — your text is never uploaded or stored.
About the Diff Checker
This free diff checker compares two pieces of text and highlights exactly what changed — additions in green, removals in red. Compare by line for documents and code, by word for prose, or character by character for small edits.
Unlike diff tools that upload and store your comparison, everything here is computed in your browser, so contracts, code and drafts never leave your device.
How to compare two texts
- Paste the original version on the left and the new version on the right.
- Pick a comparison mode: line, word or character.
- Optionally ignore case differences.
- Read the highlighted result, with a count of added and removed lines.
Which mode to use
- Line — code, config files and structured documents.
- Word — prose and drafts, where a sentence is reworded rather than replaced.
- Character — short strings, IDs and spotting a single typo.
Frequently asked questions
How do I compare two documents?
Paste one version into each box. Differences are highlighted immediately — green for added text, red struck through for removed.
Is my text uploaded or stored?
No. The comparison runs entirely in your browser, so nothing is transmitted or retained — which matters for contracts and unreleased code.
Can it ignore case differences?
Yes. Turn on 'Ignore case' and text differing only in capitalisation is treated as unchanged.
Can I compare code?
Yes. Line mode is designed for it, and Windows/Unix line-ending differences are ignored so they don't show as false changes.