OneOctave – Play-Along Piano

OneOctave turns any MIDI into a play-along. You cover a small range of the keyboard — as few as 3 keys — and the app performs every note outside your window. So even hard pieces are within reach from your very first day.

Falling notes show you exactly what to play. Anything you don't cover, OneOctave plays for you — so the music always sounds complete.

WHAT YOU CAN DO
• Start on just 3 keys, then grow to 5 keys, 1 octave, or 2 octaves
• Three ways to play — Listen (watch it perform), Play (perform in time), Learn (the song waits for each note)
• Import any MIDI (.mid) file and play along — it's saved to your library so it's never lost
• Build your own song in the MIDI editor: tap notes onto the timeline, preview, and save
• Slow the tempo, transpose to your range, or show the melody only while you learn
• Bundled beginner tunes and warm-ups so you can start right away

PRIVATE BY DESIGN
OneOctave works fully offline. There's no account and no internet connection — nothing you play or create ever leaves your device.

Recent changes:
New in 1.1 — more sounds, and a keyboard to match!

Perform any song with three new instrument voices — Organ, Strings, and Harp — alongside the two pianos. Pick one in Settings → Sound.

The play-along keyboard now takes on each instrument's look: warm wood, deep mahogany, polished gold. Prefer plain piano keys? Turn on "Default piano keys" in Settings.