WEBIDE and other Development tools
The Web Integrated Development Environment (WebIDE) is a browser-based IDE that enables software development or Web development. It can be accessed from a web browser, such as Google Chrome or Mozilla Firefox, allowing for a portable work environment. For Mozilla it was an essential component for the development of Firefox OS, but now it has come in handy for KaiOS.
WebIDE allows you to connect the Firefox Developer Tools to a number of other browsers. With it, you first set up one or more "runtimes (an environment in which you'll run and debug the app and that could be a KaiOS device or a Firefox OS simulator installed on the desktop itself)".
Next, you create an app or open an existing one. If you want to create a new app you can start with a template that includes the directory structure and the minimum boilerplate you need to get started, or a more complete template that shows how to use a privileged API.
How to install an app using WebIDE
To use any WebIDE function, your device must be debug-enabled (take a look at the DEVICES section), in which case you can access and configure it as follows:
Enable the debug mode on your device;
Connect the device to the PC using a USB cable;
Open WebIDE and connect to the "Remote runtime" (this should work on the official Kaiostr emulator), if not seen, start the "adb forward tcp:6000 localfilesystem:/data/local/debugger-socket" command and click again on "Remote runtime". If an error message about build date mismatch appears, you can safely ignore it. If the connection doesn't work, try rebooting the phone, running the "adb forward" command and connecting again. NOTE: the "adb forward" command is not needed using the offical emulator "KaiOSRT".
Select the application's folder in the "Open packaged app" button of WebIDE.
With the triangular "Play button" at the top center of WebIDE, the app will be installed on your phone.
More details on the jailbreak in the dedicated guide:
Official emulators for KaiOS 2.5 and 3.0
KaiOS RunTime, the official KaiOS emulator for Linux
KaiosRT (KaiOS RunTime) is the official KaiOS emulator. This useful tool works for any Linux distribution (not just Ubuntu). Using KaiOSRT it is possible to interact with your device by simply connecting it in Debug mode, without having to use the "adb forward" command.
KaiosRT for KaiOS 2.5 and lower:
Simulator for KaiOS 3.0:
WebIDE versions for KaiOS 2.5 or lower
Mozilla Firefox 59 or earlier (recommended for macOS)
Firefox 59 was the last version available for the Boot To Gecko development, and the last one with a workable WebIDE for KaiOS devices (older versions also work well, especially Firefox 49 or Firefox 52.9 ESR). All the Firefox releases are available for all the platforms on the official website archive.mozilla.org.
Pale Moon 28.6.1 or earlier (for Windows and Linux)
Pale Moon is a fork of Firefox with substantial divergence. The main differences are the user interface, add-on support, and running in single-process mode. It retains the highly customizable user interface of the Firefox version 4–28 era and included WebIDE until the v28.6.1 (2019-07-25). Available for Microsoft Windows and Linux (with other operating systems in development) on archive.palemoon.org.
WebIDE versions for KaiOS 3.0
Mozilla Firefox "Nightly"
Since the end of 2020, Mozilla has a partnership with KaiosTech to guarantee full support to the future builds of KaiOS, through the builtin Developer Tools of the browser. As suggested from the official guide, you can install Firefox Nightly, an unstable testing and development platform.
Alternative software to WebIDE
Small cross-platform application manager that can be also used as a NodeJS module / library.
More details on the official repository: