Amazon FireOS is an Android-based mobile operating system produced by Amazon for its Fire Phone and Kindle Fire range of EReaders, and other content delivery devices like Fire TV; the tablet-version of the Kindle Fire is the Amazon Fire HDX. It is forked from Android. Fire OS primarily centers on content consumption, with a customized user interface and heavy ties to content available from Amazon's own storefronts and services.
While the Kindle Fire line has always used customized distributions of Android, particularly 2.3.3 (API level 10) (Kindle Fire) and 4.0.3 (API level 15) (Kindle Fire HD...