Code Difference Checker

Compare two versions of code line by line, ignoring whitespace or case if you wish, and export a unified diff.

Runs in your browser. Your input is processed on your device and is not uploaded to our server.

Original Open file

Changed Open file

How to use the Code Difference Checker

Paste the original code on the left and the new version on the right.
Choose whether to ignore whitespace and case.
Click Compare, then copy or download the unified diff.

The comparison uses the Myers diff algorithm, the same approach used by Git, and shows line numbers for both versions. The unified diff output can be applied with patch or git apply. Code stays in your browser.

Frequently asked questions

Can I compare whole files?

Yes. Open each file with the file buttons; they are read locally.