to the Diffr App
The Diffr logo: two slightly overlapping diamond shapes

About Diffr

Diffr is a tool for comparing text files. It was created out of dissatisfaction with existing diffing tools (and a certain amount of paranoia because virtually every diffing tool has to send your data to their server to compare). In Diffr, all the work happens locally and your data never leaves the browser.


  • Fully local diffing removes the need for a network connection — once the app is loaded, it will continue to work even when you're offline.
  • Share your diffs with others — all diffing data is contained in the shared URL.
  • Drag&Drop files from your filesystem into the editor to compare them.
  • Full support for dark and light mode.


  • The editor which Diffr uses under the hood does not currently support mobile devices running Android. For that reason, Diffr can not support those targets either.
  • Bringing the editor and diffing experience entirely into the browser requires quite some bandwidth, which means that the whole site is pretty heavyweight (roughly 3 MB). This does not hurt past initial load since the app is cached and not loaded again on further visits, but the initial load may be an issue for users with an unstable connection or a limited data plan.

The Diffr App is Open Source software under the MIT license. Feel free to leave feedback or contribute improvements in our GitHub repository.