Fully Open-sourced Online MIDI Editor. Features - Open/Save MIDI Files - Built-in GM compatible virtual sound module - Piano Roll Editor - Multi track editing - Velocity, pitch-bend editing - Tempo Track signal is an app that I personally make as a hobby. Please forgive all kinds of bugs. If you agree with the concept of lightweight composer software that runs in a browser, please support me. I would be grateful if you could report bugs, recommend to others, and sponsorship.