MIDI (Musical Instrument Digital Interface) is a protocol used to allow music hardware, software and other equipment to communicate with each other.

MIDI is a widely-used protocol which can transmit note, controller, program, timing and vendor/hardware musical instrument specific (so called system exclusive/SysEx) information. The MIDI protocol can be used to allow your software to communicate with other MIDI-compatible software or hardware.

Some useful resources on the MIDI protocol: