How do I compare two texts?

Paste the original text in the left panel and the modified text in the right panel. Differences are highlighted instantly: green for added lines, red for removed lines.

What algorithm is used for diffing?

The tool uses the Myers diff algorithm (via the "diff" library) which produces the minimal set of edit operations — the same algorithm used by Git.

Yes — the diff checker works for any plain text including source code, JSON, YAML, Markdown, configuration files, or prose. It compares line by line.

What do the colours mean?

Green lines with a "+" prefix are additions (only in the modified/right text). Red lines with a "-" prefix are deletions (only in the original/left text). Unchanged lines have no prefix.

Is my text sent to a server?

No — all comparison runs locally in your browser. Your text is never transmitted anywhere.

Diff Checker

Compare two texts or code blocks side-by-side. Additions are highlighted green, deletions red. Uses the Myers algorithm — same as Git.

Your files never leave your device

Original

Modified

How to Diff Checker

Paste the original text in the left panel.
Paste the modified text in the right panel.
Differences are highlighted instantly — green for added lines, red for removed lines.
The summary shows total additions, deletions, and unchanged lines.

Why Use This Tool?

Comparing versions of configuration files, code, or documents is a daily task for developers and writers. This tool provides Git-quality diffs instantly, without installing any software, running entirely in your browser.

Diff Checker

How to Diff Checker

Why Use This Tool?

Frequently Asked Questions