With Pigiron, MIDI processing blocks, called 'Operators', may be freely connected to form a MIDI process graph. The following operator types are available:

ChannelFilter - filter messages by MIDI channel. Distributor - re-transmit message on any number of MIDI channels. MIDIInput - wrapper for MIDI input device. MIDIOutput - wrapper for MIDI output device MIDIPlayer - a MIDI file player. Monitor - display MIDI traffic. Transposer - manipulate MIDI data bytes.

Pigiron has a comprehensive OSC interface as well as an interactive command-line interface. It is terminal based program only implemented in Go. Currently it has only been tested on Ubunto Linux.