Text Diff Checker

Paste two versions of any text and see every added and removed line highlighted instantly — perfect for documents, essays, contracts and code.

Live — the diff updates as you type

How the Comparison Works

The checker uses a longest-common-subsequence (LCS) line diff — the same family of algorithm behind Git — so unchanged blocks stay aligned and only genuine changes are flagged. Red lines were removed from the original; green lines were added in the new version.

Everything runs in your browser: contracts, essays, articles and source code are never uploaded.

When to Use a Text Diff

  • Documents & contracts: spot what changed between two versions before signing.
  • Writing & editing: compare drafts, see an editor's changes at a glance.
  • Code & config: quick check outside your editor — pair it with our JSON Formatter.
  • Study & plagiarism checks: see how similar two passages really are. Count the words with our Word Counter.

Frequently Asked Questions

How do I compare two texts online?
Paste the original on the left and the changed text on the right — the diff updates instantly, marking removed lines in red and added lines in green with a change summary.
Is my text uploaded anywhere?
No. The comparison runs entirely in your browser — contracts, essays and code are never sent to a server.
What diff algorithm is used?
A longest-common-subsequence (LCS) line diff — the same family used by Git — so unchanged blocks stay aligned and only real changes are highlighted.
Can I ignore case or extra whitespace?
Yes — toggles let you ignore letter case and leading/trailing whitespace so cosmetic differences don't clutter the result.