|Developer||Android Open Source Project (AOSP) code: Google
|Written in||C (core), C++, Java (UI)|
|Source model||Proprietary software based on Open source Android and in all devices with proprietary components|
|Latest release||Fire OS 18.104.22.168 / December 16, 2016|
|Latest preview||Fire OS 5 Developer Preview for Amazon Fire TV / August 17, 2015|
|Marketing target||Kindle Fire, Fire HDX (tablet computers), Amazon Fire TV, Fire Phone|
|Platforms||32-bit and 64-bit ARM|
|Kernel type||Monolithic (modified Linux kernel)|
|Userland||Bionic libc, mksh shell, native core utilities with a few from NetBSD|
|Default user interface||Graphical (Multi-touch)|
|License||Proprietary EULA; based on Apache License 2.0
Modified Linux kernel under GNU GPL v2
Amazon FireOS is an Android-based mobile operating system produced by Amazon for its Fire Phone and Kindle Fire range of tablets, and other content delivery devices like Fire TV; the tablet versions of the Kindle e-readers are the Fire range. 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) (Fire HD), Amazon only began referring to the distribution as Fire OS beginning with its third iteration of Kindle Fire tablets, which includes the Fire HD 2nd generation and Fire HDX models. Unlike previous Kindle Fire models, whose operating system is listed as being "based on" Android, the Fire HDX "FireOS 3.0" operating system is listed as being "compatible with" Android; FireOS 3 is forked from Android 4.2.2, (API level 17). In the Fire HD (3rd generation) and Fire HDX (2nd generation) tablets, Fire OS 4 is included that is forked from Android 4.4.2 (API level 19). Fire OS 4.5.1 is based on Android 4.4.3. Fire OS 5.0 is based on Android 5.0 (API level 22).
Fire OS uses a customized user interface designed to prominently promote content available through Amazon services, such as Amazon Appstore, Amazon Video, Amazon MP3 & Audible, and Kindle Store. Its home screen features a carousel of recently accessed content and apps, with a "favorites shelf" of pinned apps directly below it. Sections are provided for different types of content, such as apps, games, music, audiobooks, and video among others. A search function allows users to search through their local content library or Amazon's stores. Similarly to Android, sliding from the top of the screen exposes quick settings and notifications. Fire OS also provides integration with Goodreads, Facebook, and Twitter. X-Ray is also integrated into its playback functions, allowing users to access supplemental information on what they are currently viewing. On the Fire HDX and Fire Phone, an additional function called "Mayday" allows users to connect directly to a support agent for assistance via one-way video chat. Amazon claims that most Mayday calls would be answered within 15 seconds. The OS features a user system, along with Kindle FreeTime, a suite of parental controls which allow parents to set time limits for using certain types of content.
Fire OS 5, which is based on Android 5.0 "Lollipop", uses an updated interface. The home screen now features a traditional application grid and pages for content types as opposed to the previous carousel interface. It also introduces "On Deck", a function which automatically moves content out of offline storage to maintain storage space for new content, the speed reading tool "Word Runner", and screen color filters. Parental controls were enhanced with a new web browser for FreeTime mode featuring a curated selection of content appropriate for children, as well as "Activity Center" for monitoring usage by children. Fire OS 5 removes support for device encryption; an Amazon spokesperson stated that encryption was an enterprise-oriented feature that was underused. However, in March 2016, after the removal was publicized and criticized in the wake of the FBI–Apple encryption dispute, Amazon announced that it would be restoring the feature in a future patch.
Fire OS devices are exclusively tied to Amazon's software and content ecosystems; they do not offer the Google Play Store or come pre-installed with any other of Google's proprietary apps or APIs, such as Google Maps or Google Cloud Messaging. Fire OS does provide proprietary alternatives to Google's platforms; for example, in lieu of Google Maps, Fire OS offers Here Maps with a clone of Google Maps API 1.0. As Fire OS is intentionally designed to be incompatible with Google's official Android compatibility standards, Fire OS devices do not include Google's proprietary software or use the Android trademarks. However, as with other Android devices, third-party apps can still be sideloaded via APK files, although full compatibility is not guaranteed if the app depends on Google services.
Members of the Open Handset Alliance (which include the majority of Android OEMs) are contractually forbidden to produce Android devices based on forks of the OS, therefore Kindle Fire tablets are manufactured by Quanta Computer, which is not an OHA member.
The releases are chronologically sorted and categorized based on the underlying version of their Android codebase.
The preferred license for the Android Open Source Project is the Apache Software License, 2.0. ... Why Apache Software License? ... For userspace (that is, non-kernel) software, we do in fact prefer ASL2.0 (and similar licenses like BSD, MIT, etc.) over other licenses such as LGPL. Android is about freedom and choice. The purpose of Android is promote openness in the mobile world, but we don't believe it's possible to predict or dictate all the uses to which people will want to put our software. So, while we encourage everyone to make devices that are open and modifiable, we don't believe it is our place to force them to do so. Using LGPL libraries would often force them to do so.