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Diff Checker

Compare two texts and instantly highlight what changed.

How it works

1
Paste two texts
Enter the original version in the left panel and the revised version in the right panel.
2
Compare instantly
A lightweight diff algorithm highlights additions in green, deletions in red and unchanged lines in neutral — all in your browser.
3
Switch view modes
Toggle between side-by-side and inline unified diff views to match your preference or screen size.
4
100% private
No text is ever sent to a server. The comparison runs entirely in your browser — safe for confidential documents and code.

Frequently Asked Questions

Is the Diff Checker free?

Yes, completely free. No account, no data stored.

Is my text sent to a server?

No. The diff algorithm runs entirely in your browser — your text never leaves your device.

What does the diff highlight show?

Added lines are highlighted in green, deleted lines in red and unchanged lines are shown in neutral. Both side-by-side and inline views are available.

Can I compare code or documents?

Yes. The diff checker works on any plain text including source code, configuration files, legal documents and spreadsheet data pasted as text.