iPhone · iOS 17+ · Music
Hold a chord.
Sweep the glass.
Every note lands.
The cult electronic autoharp of the early 1980s — the strum-anything machine that turned anyone into a musician — rebuilt as a real instrument for your iPhone. No theory. No tuning. No wrong notes.
Pay once, own it forever · No ads · No subscriptions · No data collected
🔊 Turn your sound on. This is a postcard — the app sounds far richer.
Why this exists
A machine that made everyone a musician
In 1981 a Japanese instrument maker put a chord panel and a touch-sensitive strumplate in a cream plastic box. It could not be played wrong. Press a button, sweep your thumb, and a shimmering, perfectly-tuned chord poured out. Songwriters loved it because ideas arrived faster than doubt. PocketStrum is that instrument, rebuilt from scratch as real-time synthesis on the phone already in your pocket — not a set of samples, and not a toy.
The originals now change hands for many hundreds of pounds, when you can find one. This one costs £4.99, fits in your jeans, and plays through your headphones on the bus.
What's inside
A complete instrument, not a novelty
Everything below is in the app today, for the one purchase price.
108 chords from twelve keys
A 3 × 12 panel in circle-of-fifths order. Hold Maj+7 for a major seventh, Min+7 for a minor seventh, Maj+Min for diminished, all three for augmented — plus dedicated Sus4 and Add9 keys. The strumplate retunes itself instantly to whatever you hold.
A real synth engine
Six voices — Omni, Harp, Celeste, Organ, Bell and Pad — from a real-time polyphonic engine with anti-aliased oscillators, shimmering delay, hall reverb and vibrato. Not a sample library. It responds to how you play.
A band in your pocket
Five rhythms — Rock, Slow rock, Waltz, Bossa nova and Hip hop — each with drums and an auto-bass that follows your chord changes. Tempo fader from 60 to 180 BPM with a running-beat LED.
Velocity from your thumb
Sweep slowly for something soft and rounded; sweep fast for bright and urgent. Every string gives a haptic tick as you cross it, so the glass feels like it has strings under it.
The chord-organ layer
A sustained pad underneath the strum, with its own volume fader — that warm held-chord-plus-sparkle sound the original hardware was famous for. Blend to taste.
Tape mode
Gentle wow and flutter, like a cassette that's been played a few hundred times. Switch it on when you want the recording to sound found rather than made.
MIDI out
PocketStrum appears as a virtual MIDI source, so the strumplate can play GarageBand, Logic, AUM or a hardware synth directly. Use it as a chord controller that nobody else has.
Plays over your music
Audio keeps running in the background and mixes with Apple Music or Spotify, so you can jam along with any track you like.
Record and share
Capture a performance and send it anywhere in one tap. Left-handed players can flip the strumplate. Works in portrait and landscape.
Learn mode
Seven songs that teach themselves
PocketStrum ships with seven demo songs that play the instrument for you. Switch on Learn Mode and each one becomes an interactive lesson.
The song pauses at every chord change. The keys you need to press light up. The moment you play them, it rolls on. Nothing scolds you, nothing scores you — it simply waits.
It's the fastest route from "I can't play anything" to "I just played a whole song" that we know how to build.
Learn Mode lights up the keys you need next
Two looks, one instrument
1981 or tonight
Classic is a cream-and-red hardware skin with bevelled plastic keys, red LEDs and ruler-ticked faders, straight out of the year it was born.
Modern is flat, dark and stage-friendly — the one you want when the lights go down and you need to find a chord fast.
Switch any time. Your choice is remembered.
Who plays it
Sketch faster. Sound better. Hand it to anyone.
Songwriters use it to get an idea down before the idea gets away. Producers use it for the shimmer a guitar can't do. And everyone uses it for the thing it does best: handing your phone to someone who says they're "not musical" and watching their face change.
- Writing songs when a guitar is in another room
- Adding a dreamy chord bed to a track in seconds
- Practising chord changes without fretting a thing
- Playing over an Apple Music or Spotify backing track
- Driving a hardware synth over MIDI as a chord controller
- Handing to a friend at 1am and losing them for an hour
Also from the same workshop
Wonderchord — for the smallest hands in the house
The same instrument, rebuilt for children aged 2–6. Twelve rainbow strings that are always in tune, six colour pads, nine songs they already know, and a lesson mode that waits patiently for a toddler.
No ads. No in-app purchases. No links out of the app. Nothing collected. Built for Apple's Kids category and COPPA from day one.
Honest by design
One price. No second act.
PocketStrum costs £4.99 and then costs nothing, ever again. There is no subscription, no unlock, no "pro voices" waiting behind a paywall, no account to make, no analytics SDK, and no data leaving your phone — the App Store privacy label says Data Not Collected, and it means it.
Requires iPhone with iOS 17 or later. 822 KB. Family Sharing supported.
Questions
Before you buy
Do I need to know any music theory?
None at all. Press a chord key with your left thumb and sweep the strumplate with your right. The strings retune to whatever you're holding, so a wrong note isn't available to you. Theory is optional and arrives later, on its own.
Is this the same as the 1980s hardware?
It's an independent tribute, not a reissue or an emulation of any specific product, and it isn't affiliated with or endorsed by any hardware manufacturer. The sound comes from a synthesis engine written from scratch. If you loved the originals, this was made by someone who did too.
Does it work on iPad or Mac?
PocketStrum is designed for iPhone. It will run on an Apple Silicon Mac and on iPad at iPhone size, but the layout is tuned for a phone held in two hands. Wonderchord is the one built for iPad.
Can I use it with GarageBand or Logic?
Yes. PocketStrum publishes a virtual MIDI source, so the strumplate can play any app or hardware synth that accepts MIDI in. You can also record inside PocketStrum and share the audio file straight out.
Will it interrupt my music?
No — it mixes. Audio continues in the background and sits on top of Apple Music, Spotify or anything else that's playing, so you can jam along.
Are there in-app purchases or a subscription?
Neither. One purchase, everything included, free updates. There is no account and nothing to cancel.
What does it cost where I live?
£4.99 in the UK; your local App Store shows the equivalent in your currency. It's a one-time purchase everywhere, and Family Sharing means up to six people in your family can use it.
Is it left-handed friendly?
Yes — there's a setting that flips the strumplate and chord panel so the chords fall under your right thumb.
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