Control the Behringer TD-3 in your browser over WebUSB / WebMIDI - edit device settings, run the step sequencer, record MIDI and check firmware, no install or drivers. Functions: General, Sequencer, PolyChain, Calibration, Update. Also known as TD-303.
Official app: SynthTribe. Connection: WebUSB discovery + WebMIDI SysEx.
Variants: TD-303.