Firefox Focus is a free and open-source privacy-focused mobile browser by Mozilla, based on Firefox. It is available for Android[4][5] and iOS smartphones and tablets.[6][7] Its predecessor, Focus by Firefox, was released in December 2015 as a tracker-blocking application which worked only in conjunction with the Safari mobile browser on iOS.[8][9] It was developed into a minimalist web browser in 2016 but retained this background blocking functionality.[10]
The Android version of the browser was first released in June 2017 and was downloaded over one million times in the first month.[11] As of January 2017, it was available in 27 languages.[12] The version released for German-speaking countries has telemetry disabled and is named Firefox Klar to avoid ambiguity with the German news magazine FOCUS.[13][14]