What language is needed to develop extensions

[oseamiya]

You need to know java 7 or java 8 if you use rush. You can also use Kotlin to write code using rush.

Configuring your computer to build App Inventor 2 extensions

Writing your first App Inventor 2 extension

Rush • A new and improved way of building extensions

[banner] Rush is a build tool, built to be a complete replacement for the existing way of developing extensions. It attempts to improve the overall developer experience and reduce the amount of boilerplate code you need to write to make extensions. With Rush, you no longer need to use annotations to define your extension’s metadata and Android manifest tags. Instead, you get a separate metadata file, rush.yml, and direct support for AndroidManifest.xml (more on that below). Not just that, Ru…

You can search How to create extension , you will find many articles.