Paste or upload two versions of text and see them compared column by column — original on the left, updated on the right.
Upload original file
Drag a text file here, or click to choose
Upload updated file
Drag a text file here, or click to choose
The diff algorithm runs in a Web Worker inside your browser, so the page stays responsive even for large files. The text you compare is never sent to a server.
All diffing is done locally using browser APIs. The content you paste or upload never leaves your browser tab — no server receives it at any point.