Paste two versions and see which lines were added and which were removed. Useful for contracts and config files — both things you would rather not paste into a server you do not control.
This page loads no libraries at all — the work is done by the browser itself.
Your file is read on your own machine and never sent anywhere — open your
browser's network tab and watch while you use it.
Questions
Is this a proper diff?
It is a line-by-line comparison, not a full alignment algorithm. If you insert a line at the top, everything after it shows as changed — good enough for spotting edits, not for merging code.
Does it compare words within a line?
No, whole lines only.
Other text & code tools
Everything here is free and works the same way — in your browser.