RandomMIDI produces 'random' sequences of pitches from notes played on an on-screen piano keyboard image. Randomly assigned note duration values range from whole- to sixteenth-notes. The sequences are saved as 'type 1' MIDI files using the default piano sound (GM voice 1) at 120 BPM (beats per minute). The voice and tempo can, of course, be changed by the MIDI file-playing application or device. Files produced by RandomMIDI open by default with the QuickTime Player application.

Entering a note more than once will 'weight' the sequence towards that note; this can be useful in creating more tonal-sounding sequences.