Wikipedia:Vada

Vada is a multithreaded, Wikipedia framework based in the browser, designed to make it easy to develop tools such as AWB, Huggle and STiki that run in the browser. (Editing Wikipedia from the browser is a lot less crazy than it sounds.) It is being developed by A930913 and is currently in alpha testing.

How to use Vada
Vada/Tutorial explains how to install and use Vada.

Why Develop with Vada?

 * Vada runs entirely within the browser (though plugins can use backends if they wish). This means that users do not need to download or install any software.
 * Vada is written for the developer. The usual pains of coding for the web are considerably lessened.
 * Vada runs synchronous code. There are no callbacks, which means you won't end up with spaghetti or deeply nested code.
 * Vada does not use callbacks.
 * Vada does not use callbacks. You always know where you are in the code, because the previous line has just run.
 * Vada does not use callbacks. If you think this means the GUI will freeze, you're wrong.
 * Writing code for Vada means it will work on any OS with a good browser. (Windows, Linux, Mac, etc.)
 * It's in the cloud, man.

How to Develop with Vada
There is some documentation, however this is somewhat outdated. The currently preferred method is to go on IRC to or  and mention a930913 saying what you want to do with Vada.