Text Diff Checker

Compare two texts and highlight the differences.

Differences will be shown here.

About the Text Diff Checker

The Text Diff Checker highlights exactly what changed between two versions of a text. Paste a contract and its revision, two drafts of an article, two configuration files or two blocks of code, and the tool marks every added and removed line so you can review changes without reading both documents end to end.

Because the comparison runs locally in your browser, it is suitable for confidential material. The result can be scanned quickly: red lines were removed from the original, green lines were added in the modified version, and everything else is unchanged.

How to use the Text Diff Checker

  1. Paste the original text into the left box and the modified version into the right box.
  2. Optionally tick "Ignore case" or "Ignore whitespace" to hide differences that do not matter to you.
  3. Click Compare. Removed lines are shown in red with a strikethrough, added lines in green, and unchanged lines in plain text.

Frequently asked questions

How does the diff work?

The tool compares the two texts line by line using the longest-common-subsequence algorithm, the same approach used by classic diff utilities and version-control systems. It finds the minimal set of added and removed lines that turns the first text into the second.

Can I compare code?

Yes. Indentation and tabs are preserved. Enable "Ignore whitespace" if you only care about changes to the actual code and not to formatting.

Is there a size limit?

The comparison runs in your browser, so very large inputs depend on your device. Texts up to several thousand lines each compare in well under a second on a typical laptop.

Are my documents uploaded?

No. Both texts stay in your browser. This makes the tool safe for contracts, drafts and source code.