What is KaiOS? A Complete Beginner’s Guide [2024]

Richard Goodwin

03/25/24 •  8 min read

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Here’s literally everything you need to know about KaiOS, a Linux-powered mobile OS for phones with traditional keypads that also lives a double life in the hands of modders as a custom ROM

Developed by KaiOS Technologies (Hong Kong) Limited, with TCL Corporation as its largest shareholder, KaiOS is a mobile Linux distribution that brings the power of smartphones to smaller, cheaper traditional keypad phones – you know, like the T9 phones like we used to have in the late-1990s.

You probably haven’t heard of KaiOS before, and that’s understandable: 99.9% of the smartphone market is dominated by Android and iOS. But the bulk of its framework comes from Mozilla’s Boot 2 Gecko framework which, back in and 2012, was initially positioned as another, more open way to run smartphones.

KaiOS is not a big operating system nor will it give Apple or Google any pause for thought. But for emerging markets where money is tight and for modders and open-source tinkers, KaiOS is presents something new and something very interesting.

What is KaiOS?

Built on a fork of the Boot to Gecko project (B2G), which underpinned Firefox OS, KaiOS is based on open web standards and primarily uses HTML5, JavaScript, and CSS for application development. This approach allows for the creation of lightweight apps that run efficiently on low-end hardware.

This is why you’ll mostly find KaiOS in small, compact phones with T9 keyboards. Unlike iOS and Android, and other platforms like HarmonyOS by Huawei, KaiOS is built for and aimed squarely at emerging markets where price is everything.

KaiOS supports 4G LTE connectivity, Wi-Fi, and GPS, and prices typically range from anywhere from $17 to over $100 – the more features it has, the higher the cost. But the idea behind the project is simple: outfit modern phones with modern features and apps at prices everybody can afford – not just westerners.

Device Support and Availability

KaiOS is available on a range of feature phones from global brands such as Nokia, Alcatel, and JioPhone.

The operating system supports devices with T9 keypads, and some models even feature QWERTY keyboards. KaiOS is currently available in 88 languages, making it accessible to users worldwide.

KaiOS Technologies has formed strategic partnerships with industry giants like Mozilla, Google, and Facebook. Unlike Huawei’s HarmonyOS, this means you can actually run popular apps on phones powered by KaiOS.

These collaborations have been instrumental in developing the platform and expanding its reach. For example, the partnership with Mozilla in March 2020 focused on updating KaiOS with modern web technologies.

“Mozilla is happy to partner with KaiOS, a company that shares our commitment to an internet that includes all the peoples of the earth. A version of Gecko, the implementation of the Web Platform in Firefox, is currently used by KaiOS to render the web on their devices.

This partnership will help ensure that KaiOS remains a robust and secure web platform by bringing their version of Gecko more up to date, and keeping it up to date with the latest features, web site compatibility, and security fixes.

This partnership is an example of how Mozilla can partner with other groups that wish to use Gecko, leveraging the tools and services that the Mozilla team uses to ship Firefox today.” said Joe Hildebrand, Mozilla’s Vice President of Web Platform.

Best KaiOS Apps and Applications

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One of the biggest issues with iOS / Android alternatives is that they lack support for core apps we all know and love. This is why KaiOS, despite the fact it runs on much lower spec hardware than most Android phones, has support for apps like Google Assistant and YouTube. 

By creating partnerships with key players in the tech space, including the aforementioned Mozilla one, KaiOS has been able to bring some of the most used and useful apps on the market to its ultra-affordable phones. 

And for users in emerging markets, this makes a huge difference. Most feature phones don’t even run 4G or support WiFi. KaiOS phones have both, and other technology like GPS and advanced web technologies built into them natively. 

Some popular KaiOS applications include:

1. WhatsApp: The popular messaging app is available on KaiOS, allowing users to send messages, make voice and video calls, and share media.
2. Google Assistant: KaiOS devices come with Google Assistant integrated, enabling users to perform tasks and access information using voice commands.
3. YouTube: Users can watch videos on the go with the YouTube app for KaiOS.
4. Facebook: Stay connected with friends and family using the Facebook app optimized for KaiOS devices.
5. Google Maps: Navigate and explore with the lightweight version of Google Maps designed for KaiOS.

Jailbreaking and Custom ROMs

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The debut of the Nokia 8110 4G, often referred to as the “Banana Phone” due to its distinctive curved design, marked a significant moment in the KaiOS ecosystem.

This event garnered attention from tech enthusiasts and developers who saw potential beyond the platform’s intended limitations. They embarked on developing methods to “jailbreak” KaiOS devices, a process that enables users to bypass the system’s restrictions.

Jailbreaking KaiOS devices opens up several possibilities not officially sanctioned by the operating system’s creators.

One of the primary advantages is the ability for users to install applications from sources other than the KaiStore, expanding the range of software available to them.

This capability is especially appealing to those who wish to use apps that are not officially supported or available in the KaiStore.

GerdaOS & The Push For More Open Web Standards on Phones

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Jailbreaking allows for the flashing of custom ROMs, such as GerdaOS, onto KaiOS devices.

GerdaOS is probably the most well known custom ROM developed specifically for KaiOS phones. It offers an alternative operating system experience, with features and optimizations not found in the official KaiOS firmware – the emphasis is on security, privacy, and the removal of ads and tracking technology.

As with a lot of things in the open source world, the development on these KaiOS custom ROMs is built around a set of ethical philosophies (the kind not shared by the Apple and Google’s of the world).

The very decision to create GerdaOS was initially made after finding a devastating security bug in the KaiOS version shipped with Nokia 8110 4G (v13 and earlier HMD firmware versions).

GerdaOS doesn’t have any pre-installed apps that are proven to track you, including but not limited to KaiStore, FOTA updater, Gameloft games and all Google apps. Also, it has analytics disabled and “Do Not Track” header enabled by default, and the default browser search engine is set to DuckDuckGo.

Moreover, it has the most comprehensive host-based advertisement blocking list to this day. So your surfing experience won’t be distracted by this plague of modern web.

GerdaOS

Richard Goodwin

Richard Goodwin is a leading UK technology journalist with a focus on consumer tech trends and data security. Renowned for his insightful analysis, Richard has contributed to Sky News, BBC Radio 4, BBC Radio 2, and CNBC, making complex tech issues accessible to a broad audience.