Text Diff Checker

Compare two blocks of text and highlight the differences line by line.

What Does the Text Diff Checker Do?

The Text Diff Checker compares two versions of a text line by line and highlights exactly what changed: lines that were removed appear in red with a minus sign, lines that were added appear in green with a plus sign, and unchanged lines stay neutral for context. A summary tells you at a glance how many lines were added and removed — or confirms that the two texts are identical.

The comparison uses the same longest-common-subsequence algorithm family that powers developer tools like git diff, so the output feels familiar and precise. Options let you ignore case differences and leading/trailing whitespace, which is handy when formatting noise would otherwise drown out the real edits.

How to Use the Diff Checker

  1. Paste the original text into the left box.
  2. Paste the changed version into the right box.
  3. Optionally tick "Ignore case" or "Ignore leading/trailing spaces".
  4. Click Compare Texts and read the highlighted result.

When a Diff Checker Saves the Day

  • Contract and document review — see exactly what a counterparty changed between two versions of an agreement.
  • Editing and proofreading — compare a draft against the edited copy to review every alteration.
  • Code review without a repo — diff two config files or scripts that were never committed to version control.
  • Content audits — check what changed between two exports of a product description or web page.
  • Duplicate detection — verify whether two similar-looking documents actually differ.

Frequently Asked Questions

Does the tool compare word by word or line by line?

Line by line. Each line is treated as a unit, and the algorithm finds the smallest set of added and removed lines that turns the first text into the second — the same approach used by git.

The texts differ only in capitalization — can I ignore that?

Yes, tick "Ignore case" before comparing. Lines that differ only by upper/lower case will then be treated as identical.

How big can the two texts be?

Documents of a few thousand lines each compare in well under a second. Extremely large files (tens of thousands of lines) still work but may take a few seconds, since everything runs in your browser.

Are my documents uploaded for comparison?

No — the diff is computed locally in your browser. Both texts stay on your device, so the tool is safe for confidential contracts.