The easiest FREE way to check who unfriended you on Facebook!
Unfriend Checker is an app available from 2014 with over 20K members.
As functionality, this app will read and save your Facebook friends list and will compare results each time when the app is executed.
App can detect also deactivated accounts.
App is available as a browser add-on or extension on desktop computers for Firefox and Chrome.
We are preparing in next short future the same functionality available for mobile devices.