|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 |
GNU GPL v2 for Linux kernel modifications 
KaiOS is a Linux-based mobile operating system that "merges the power of a smartphone with the affordability of a feature phone". It is forked from B2G (Boot to Gecko), an open source community-driven successor of Firefox OS which was discontinued by Mozilla in 2016.
Primary features of KaiOS is to bring support for 4G LTE E, 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. 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.
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.
Devices that come with KaiOS include:
- Alcatel OneTouch Go Flip (known as Cingular Flip 2 on AT&T)
- Reliance Jio JioPhone, JioPhone F101K, F10Q, F120B, F220B, F300B, F30C, F41T, F50Y, F61F, F81E, F90M, LF-2403N, JioPhone 2.
- 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 
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