PocketMIDI: MIDI Keyboard

PocketMIDI is a low-latency MIDI synthesizer and piano for Android, built for live performance. The core app is completely free — and everything it did for free before, it still does for free.

Plug in a USB MIDI keyboard or play the on-screen keys: studio-quality sound with a latency target under 40 ms. No ads, no tracking, no subscription, no account.

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FREE — AND STAYING FREE
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No trial, no sign-up:
• Four built-in instruments — Grand Piano (Salamander V3, A0–C8), Strings, Dark Pad, Synthesizer
• USB MIDI keyboards and the multi-touch on-screen keyboard, 96-voice polyphony, velocity and sustain pedal
• Arpeggiator, chord mode, transpose, metronome
• Full synth editor — waveforms, ADSR, filter
• Presets: save, load, export, import
• Recording with piano roll and playback, exported as WAV or M4A audio
• Performance monitor and every setting

No feature that was free has been moved behind a purchase, and none will be.

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OPTIONAL ADD-ONS
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Want a bigger palette? 23 extra instruments are one-time purchases — buy them one at a time, or unlock all of them together. No subscription.

• Keys — Upright Piano, Organ
• Strings — Solo Violin, Violin Section, Viola Section, Cello Ensemble, Solo Contrabass, Harp
• Brass — Trumpet, French Horn, Tenor Trombone
• Woodwinds — Flute, Piccolo, Oboe, Clarinet, Bassoon
• Percussion — Marimba, Xylophone, Glockenspiel, Tubular Bells, Timpani
• Bass — Finger Bass, Pick Bass
• Plus .mid export of your recordings, for editing as notes in a DAW — included with the all-sounds unlock

Preview any add-on before you buy. Packs download on demand so the app stays small, then work offline like any built-in sound, with the same ADSR editor. Purchases are one-time and restore when you reinstall or change device.

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FEATURES IN DETAIL
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USB MIDI — connect any class-compliant keyboard over OTG. Note on/off and sustain (CC64) route straight to the audio engine. Optional auto-launch on connect.

ON-SCREEN KEYBOARD — 2 octaves (C3–C5), up to 10 simultaneous touches, tap position sets velocity.

ARPEGGIATOR — patterns, rates including triplets, octave span, gate, latch. Tap-to-type BPM synced with the metronome. Chord mode fires full chords and arpeggios as you play.

SYNTH EDITOR — sine, saw, square, triangle; ADSR (attack and decay 1 ms–4 s, sustain 0–100%, release 1 ms–8 s); low-pass filter with cutoff and resonance.

PRESETS — name and save instrument and synth settings, recall them instantly mid-performance, export and import as JSON.

RECORDING — real-time piano roll, fixed-timeline playback with a moving playhead, pinch to zoom, drag to seek.

METRONOME — 20–300 BPM; time signatures 2/4, 3/4, 4/4, 6/8, 7/8, 5/4; visual pulse.

PERFORMANCE — live monitor for active voices, buffer size, sample rate, estimated latency and underruns.

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SUPPORT
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Free and paying users get the same support at the same priority. A bug in the free app is fixed with the same urgency as one affecting a purchase — buying doesn't move you up the queue, and not buying doesn't move you down it.

jdevstudiocomm@gmail.com
https://pocketmidi.jdevstudio.app/support.html

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TECHNICAL
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Oboe 1.9.0 (AAudio, OpenSL ES fallback) • ~4 ms buffer @ 192 frames, 48 kHz • automatic stream restart • Android 8.0+. Plays fully offline; the internet is used only to browse, preview and download add-ons.

Salamander Grand Piano V3 samples by Alexander Holm, used under CC BY 3.0 with no modifications: https://creativecommons.org/licenses/by/3.0/