Text Diff Checker
Paste two versions of a text and see exactly what changed — additions in green, deletions in red, line by line. Nothing is uploaded.
How the comparison works
The tool uses the longest-common-subsequence algorithm — the same principle version control systems use for diffs. It finds the lines both texts share, and everything outside that backbone is marked as added or removed.
Paste both versions
Original on the left, changed version on the right — contracts, essays, code, configs.
Tune the matching
Ignore case or whitespace when formatting noise would otherwise drown out real changes.
Read the diff
Green lines were added, red lines removed, grey lines are identical — plus a change summary.
Where a diff beats re-reading
Reading two versions of a two-page document side by side takes minutes and still misses the changed number in clause 7. A diff makes every change unmissable in seconds. Typical uses: checking what a counterparty actually edited in a contract draft, verifying that a "small fix" in a config file really only touched one line, comparing email or product templates across markets, and reviewing your own edits before sending a text back. Since everything runs locally, confidential documents never leave your machine.
Frequently asked questions
How does the diff tool compare texts?
It uses the longest common subsequence algorithm — the same principle behind version-control diffs. Lines present only in the original show as removed, lines only in the new text as added, and matching lines as unchanged.
Can I ignore case or extra spaces when comparing?
Yes — the ignore-case option treats "Hello" and "hello" as equal, and the ignore-whitespace option collapses spacing differences, so only real content changes are flagged.
Is my text uploaded anywhere?
No. The comparison runs entirely in your browser, which makes the tool safe for contracts, code and other confidential text.
What is this useful for?
Spotting what changed between two versions of anything: contract drafts, essays after edits, config files, email templates, product descriptions — anywhere reading both versions side by side would take too long.