Text · Free Tool
Text Difference Checker
Compare two texts line by line and instantly highlight added, removed, and unchanged lines.
About this tool
This diff checker compares two blocks of text line by line using a longest-common-subsequence algorithm — the same approach used by version-control tools like Git. Removed lines are highlighted in red, added lines in green, and unchanged lines stay neutral.
Use it to review document revisions, compare configuration files, spot changes between two versions of code, or verify what an editor changed in your copy.
Common uses
- Compare two versions of a contract or article to see what changed
- Check differences between two configuration or environment files
- Verify a code snippet against the original before pasting it
Frequently asked questions
Does it compare word by word or line by line?
It compares line by line, which is the clearest way to review documents and code. Split long paragraphs into shorter lines if you need finer-grained comparison.
Is there a size limit?
The tool comfortably handles a few thousand lines per side in the browser. Extremely large files may slow down since all processing happens locally on your device.
Is my data uploaded to a server?
No. This tool runs entirely in your browser using JavaScript — nothing you type is transmitted, logged, or stored anywhere. You can even use it offline once the page has loaded.