It is created with jsmidgen for exporting MIDI files, tone.js for the webaudio API, tonal for music theory (chords and scales) and a homegrown pattern language that helps you quickly put together musical ideas. It also consists of an API to help you put together a browser based music production application.
Scribbletune is a free and open source project created & maintained by Walmik Deshpande. It is currently in active development thanks to it’s awesome contributors. The logo for Scribbletune has been graciously contributed by Zuur Willem.