Slack Original author(s) Stewart Butterfield, Eric Costello, Cal Henderson, and Serguei Mourachov[1] Developer(s) Slack Technologies Initial release August 2013 (2013-08)[2] Stable release(s) [±] iOS 3.22 / June 22, 2017 (2017-06-22)[3] Android 2.18.0 / September 26, 2016 (2016-09-26)[4] Windows 2.2.1 / September 17, 2016 (2016-09-17)[5][6] macOS 2.4.1 / January 10, 2017 (2017-01-10)[7] Chrome OS 1.0.3 / December 6, 2013 (2013-12-06)[8] Windows Phone 2016.913.0.0 / September 13, 2016 (2016-09-13)[9] Written in Electron (C++, JavaScript, ECMAScript, etc.)[10] Operating system Windows, macOS, Linux, iOS, Android, Windows Phone,[11] Commodore 64[12] Type Collaborative software[13] License Proprietary Website slack.com