Compare two versions of any text side by side, with every added, removed and changed line marked and the differing words picked out inside the line. The page opens on a sample you can edit, so there is nothing to load first — and nothing to upload: every comparison runs in your own browser.
Free, with no sign-up and no install.
No. The comparison runs entirely in your browser — the documents you paste or drop in never leave your device, and there is no account and no server to store them.
Drop a file into each pane, or paste the two versions in, and press Compare. Added, removed and changed lines are marked down both sides, and the words that differ are picked out inside each changed line.
A 2-way comparison shows how two versions differ. A 3-way merge takes the version both sides started from as well, so it can tell which side made each change and only ask you about the lines both sides touched.
Documents of 50,000+ lines compare without trouble. The panes are virtualised, so scrolling stays smooth well past the point where a plain textarea would stall.
JavaScript must be enabled to use the tool.