|Developer||KaiOS Technologies Inc.|
|OS family||Firefox OS/Open Web (based on Linux kernel)|
|Marketing target||Mobile phones|
|Package manager||KaiOS Store|
|Kernel type||Monolithic (Linux)|
|Default user interface||Graphical|
|License||Closed source, Linux kernel patches under GPLv2|
KaiOS is a mobile operating system based on Linux, owned by KaiOS Technologies, a US-based company. It is forked from B2G (Boot to Gecko), an open source community-driven successor of Firefox OS which was discontinued by Mozilla in 2016.
The primary features of KaiOS bring support for 4G LTE E, VoLTE, GPS and Wi-Fi with HTML5-based apps and longer battery life to non-touch devices with optimized user interface, less memory and energy consumption. It also features over-the-air updates. A dedicated app marketplace called KaiStore enables users to download applications. Some services are preloaded as HTML5 applications, including Twitter, Facebook and YouTube. The operating system is comparatively lightweight on hardware resource usage, and is able to run on devices with just 256 MB of memory.
The operating system first appeared in 2017 and is developed by KaiOS Technologies Inc., a San Diego, California-based company headed by CEO Sebastien Codeville with offices in other countries. In June 2018, Google invested US$22 million in the operating system. India-based telecom operator Reliance Jio also invested $7 million in cash to pick up a 16% take in the company.
In market share study results announced in May 2018, KaiOS beat Apple's iOS for second place in India, while Android dominates with 71%, albeit down by 9%. KaiOS growth is being largely attributed to popularity of the competitively-priced JioPhone.
In Q1 2018, 23 million KaiOS devices were shipped.
KaiOS devices are available on various markets globally.
- Burkina Faso
- Central African Republic
- Democratic Republic of Congo
- Ivory Coast
- Sierra Leone
- South Africa
- Saudi Arabia
- United States
Devices that come with KaiOS include:
- Alcatel Go Flip (known as Cingular Flip 2 on AT&T and Alcatel MyFlip on TracFone Wireless)
- Reliance Jio's JioPhone, JioPhone F30C, F101K, F10Q, F120B, F220B, F41T, F50Y, F61F, F81E, F90M, LF-2403N, all branded as LYF, JioPhone 2, F300B, F310B
- HMD Global's Nokia 8110 4G (runs Smart Feature OS, a KaiOS-based platform)
- Doro 7050/7060
- CAT B35
- Maxcom MK241, MK281
- WizPhone WP006. Launched on Indonesia in Partnership with Google and Alfamart 
- MTN 3G phone (MTN Smart S 3G) 
- Positivo P70S (Brazil)
- Multilaser ZAPP (Brazil)
With the release of the Nokia 8110 4G, an active community around both KaiOS and the phone arose and released the first version of a jailbreak. This gave users the ability to use old Firefox OS apps on the KaiOS devices, as well as flashing their devices with community created ROMs, such as GerdaOS.
As of February 2018, KaiOS Technologies has partnered with Airfind, Facebook, Google, Twitter, Bullitt, Doro, HMD Global, Micromax, NXP, Spreadtrum, Qualcomm, Jio, Sprint, AT&T, T-Mobile, and Orange S.A.
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