Don't underestimate the dumbphone: an introduction to the KaiOS ecosystem

Peoples' first impression on seeing a button phone or "dumbphone" in 2025 is either nostalgia, "Snake", or that it is a limited device which can only make phone calls. However, having buttons is only the physical form of a device, and there is no reason for such a device to be technologically limited.

I carry a flip phone running KaiOS as a primary device, and am the developer of Convo which is a prototype messaging app for KaiOS using the XMPP protocol. I have also recently been awarded a grant from the NGI Zero Commons Fund to develop Convo into a full-fledged application.

I aim to make this talk interactive, so the direction is partly to be decided by the audience, but I will be covering four broad areas:

1. My personal opinions on dumbphones, specifically the flip-phone form factor, and why I've chosen to use one (no, it's not only about "being disconnected").

2. A brief history of the KaiOS operating system from a historical perspective, including how it fits into the general dumbphone market. I will also go into the state of the market today and its future which at times seems uncertain while at others seeming to have untapped potential.

3. How to develop your own KaiOS apps using the familiar technologies of HTML, CSS, and JavaScript (including your favourite web framework, as long as it's light enough!). I say "KaiOS" but these apps can actually be ported to CloudMosa's CloudPhone and potentially other web-based dumbphone ecosystems that come up. I will aim to provide a general how-to on developer setup, as well as introduce the "BananaHackers" third-party app store and outline some of the things to look out for based on my experience developing Convo.

4. Some ideas on what's missing in KaiOS at the moment, such as QR code payments and ride hailing. In other words: what apps there could be a good market for if you decide to develop them!

Besides my personal phone which is a Nokia 2720 Flip, I will also be bringing a spare Nokia 8110 "Bananaphone" for people to test out after the talk.

• Not all phones have to be a (potentially foldable) rectangular slab

• Dumbphone users come in two three categories: low income, looking for a cheap phone; high-income, looking to be less connected; and I who just want an ergonomic form factor.

• Developing KaiOS apps is easy: you just need your existing webdev skills and a web browser; the older the better

• Developing KaiOS app is hard: you need to learn to optimise your code right from the very beginning

• Life hack to reduce the times people try to overcharge you