MIDISLAYERDownload
⟢ real-time MIDI ⟣⟢ 9 modes + arcade ⟣⟢ one-time purchase ⟣

Slay every
note

MidiSlayer listens to your MIDI piano and judges every note in real time. Train like it matters, play like it's a game, buy it once.

Download for free
macOS Windows Linux launching 2026

How it works

Playing in about a minute.

Three moves to set up, then MidiSlayer gets out of the way and just listens. No card, no trial clock, no tutorial to sit through.

Step 01

Download it free

MidiSlayer for macOS, Windows or Linux. No card, no trial clock ticking.

Step 02

Plug in your piano

Any USB or Bluetooth MIDI keyboard. No keyboard yet? The on-screen one gets you going.

Step 03

Play. It listens.

Every note judged the instant you play it. Miss one and it comes back. That is the whole loop.

Free to start One-time purchase, no subscription Works fully offline Yours forever

Love it? Unlock the full version whenever you want. One payment, no clock, no pressure. The free version never expires.

Download for freeSee everything inside →

The whole app

See it. Play it. Go again.

Three ways to show up: Train, Games, Practice. One honest loop under all of them: a prompt, your real piano, an instant verdict.

Read the staff

Build the shapes

Own the harmony

Note Flashcards

A note lands on the staff, you play it, the verdict is instant. The foundation of it all.

staff readingrecall speed
01 / 09

The engine

The algorithm holds a grudge.

Fluff a note and it takes it personally. Every miss goes in the book, and the book decides what you see next: your problem notes, slipped back in among the easy ones, again and again, until they quietly stop being your problem notes. Nobody builds a playlist. You just look up one day and the hard bits went silent.

It aims where it pays

Spaced repetition, but the deck is yours. Miss a note and it comes back sooner and more often. Nail it and the engine pushes it further out and moves on. No settings, nothing to build.

reviewed in 1 day → 6 days → ×2.5 further out, every time it sticks. miss it and the clock resets to day one.

the deck, live re-dealt until they behave

A stream of notes flows past a review point. Weak notes appear more often and glow; mastered notes drift past once and recede.

F♯4 and E♭4 keep coming around. The rest have earned their space.

Train · help on

No clock, hints when you fumble, the deck bending around your weak spots. This is where the grudge is on your side.

Exam · help off

Timed, silent, no second chances. Whatever number it spits out is the one that becomes your rank.

Make it yours

Your drill, your dials.

Every mode ships with real dials: clefs, note pools, ranges, display, ledger lines, exam length. Harder settings multiply your exam score, so the grind is always opt-in. Crank it and watch:

Note pool
Clef
Display
Range
score multiplier×1.00honest

These are the app's actual numbers, straight from its scoring engine.

and that's one mode · chords add qualities + inversions · arpeggios add octaves + patterns · exams run 1, 3 or 5 minutes

Can't read music yet?

The course is inside.

Seven short lessons, from what a staff is to reading in a key, with real engraved examples and no video. The lessons are free, cover to cover.

Lesson 02engraved, not video

The staff, and how to read it

EGBDF

Treble lines · E G B D F

Each lesson ends by handing you straight to the training mode that drills it, so the thing you just read is the thing you play next.

Bring your own music

From flashcards to Für Elise.

Flashcards build the reflex; sooner or later you want to play something real. Drop in any MusicXML, or pick one of the 69 in the box, and MidiSlayer walks a cursor across the staff and grades every note. Two ways to run it:

Wait mode

learn the piece

The cursor waits on each beat until you play it. Chords stack one note at a time, ties count once, rests step aside. Crawl through at your own pace: rhythm is scored on proportion, not the clock.

Tempo mode

hold to the clock

Count-in, metronome, a cursor that walks whether you're ready or not. Every note lands perfect, good or miss, and a miss doesn't stop the music. At the end it tells you, to the millisecond, whether you rush or drag.

Listen

Press Listen and the app plays the score itself, cursor riding along, at any tempo. Hear it before you attempt it, or loop a few bars. Whole library and your own files, free.

Timing comes off your keyboard's hardware timestamps, corrected for audio latency. If you can feel ten milliseconds of lag, so can we, and we grade like it.

69 scores in the box

Twinkle, Twinkle at one end, Chopin's Ballade No. 1 and the complete Goldbergs at the other, and room for whatever you drag in.

  • Beginner

    Nine starters. Single lines, both hands, no surprises.

    Twinkle, Twinkle Ode to Joy freeFrère Jacques Chopsticks Tarantella Napoletana + 4 more

  • Intermediate

    Twenty-three pieces. Minor keys, compound meter, real repertoire steps.

    Greensleeves freeFür Elise (main theme) simplifiedGymnopédie No. 1 Prelude in C, BWV 846 Burgmüller · Arabesque Canon in D simplified+ 17 more

  • Advanced

    Twenty-six works, uncut. Chopin, Debussy, Joplin, the Lieder.

    Clair de Lune freeMoonlight Sonata, I. Nocturne Op. 9 No. 2 Maple Leaf Rag Schubert · Ave Maria Rondo alla Turca + 20 more

  • Virtuoso

    Eleven summits. For the day the flashcards feel small.

    Fantaisie-Impromptu freeBallade No. 1 Liebestraum No. 3 The complete Goldberg Variations Erlkönig + 6 more

Every score is free to browse and Listen to; one piece per shelf is free to play-through, and the rest, plus your own scores, come with the full version. Every edition is public domain or CC0 with per-piece credits in the app. Where a piece is a cut-down arrangement, the label says so. Nobody here is pretending a main-theme Für Elise is the whole Für Elise. The Advanced shelf has the real one.

Bring your own

Sixty-nine scores. Or every score ever written.

The sixty-nine are just the on-ramp. Load any MusicXML you own (your exam piece, your teacher's arrangement, a movement you've been circling for years) and MidiSlayer engraves it on the spot, light or dark, zoomed to taste.

Wait mode and tempo mode grade every note, yours and ours alike. Everyone else rents you a catalogue by the month; buy MidiSlayer once and your music stand becomes the library. No subscription, nothing to age out of.

Short on files? OpenScore hands out the classics free, and MuseScore has thousands more. We don't lock the door. Bring all of it.

MidiSlayer tempo mode with Schubert's Ave Maria loaded from MusicXML: the score engraved on a light sheet, a beat cursor, metronome and Start controls.
Ave Maria, loaded from MusicXML · tempo mode
Light or dark sheetZoom 50–200%Remembers how you left itYour scores wait under Recently loadedFully offline, nothing phones home
Download for free

Free to download, taste pieces included. The full version plays everything else, yours too.

The receipts

Your playing, measured.

Every attempt is recorded, per note: what you miss, where you hesitate, when you show up. Practice stops being a black box.

MidiSlayer progress page with rank ring, stats and the rank ladder
The climb

Five ranks, one ladder per skill.

Exam scores stack into a rank. Every skill ranks separately: reading the staff and naming notes are different muscles, so each climbs its own ladder. Your headline rank is just the highest peak you've reached, and the top is a real grind.

  1. Maestro100,000 pts
  2. Virtuoso28,000 pts
  3. Musician7,000 pts
  4. Apprentice1,500 pts
  5. Novice0 pts
also in the box
  • Consistency calendar
  • Note weakness map
  • Slowest notes
  • First-try accuracy
  • Exam score & rank
Private by design

No ads. No tracking.
No telemetry.

Your practice data lives in a local database on your machine. Your weak notes are your business.

It evolves

v1 is the start, not the deal.

Getting from zero to here took nine modes, three arcade games with a shared daily run of Cascade, Score Practice with a 69-piece library you can play or just listen to, and an analytics suite that measures what you actually retain. That pace doesn't stop at launch, and updates within v1 are free.

  1. always on

    Sharpening what shipped

    Early-access feedback, folded in fast. Rough edges filed as they surface, and the loudest requests jump the queue.

  2. exploring

    The Session, deeper

    A bigger band: richer backing, more changes to jam over, coaching that listens harder to what you play.

  3. planned

    MidiSlayer on iOS

    The full trainer on iPad, where a staff has room to breathe. Phones are a squeeze for sheet music, so tablets lead.

  4. everywhere · planned

    MidiSlayer on Android

    Then Android tablets too, so nobody is locked out of their own repertoire.

The order is partly yours to call.

We read everything, and the roadmap bends toward what players actually ask for. Buy early, get loud, watch the app grow around you.

Tell us what you need

The deal

Buy it once. No subscription.

A practice tool is more like a metronome than a streaming service. Pay once, use it for good. Free updates through v1, no monthly bill, and it's still sitting there when you crawl back to the piano after a year off. Your cancelled subscription wouldn't be.

One payment costs about what three months of a practice-app subscription does. Then it stops asking.

Free

$0

forever · no card, no clock

  • ♪Note Flashcards, the full mode, no strings
  • ♪Blitz in full, plus one free Cascade run a day (the Daily Challenge)
  • ♪Improvise in The Session over the Pop Loop
  • ♪The complete course on reading music
  • ♪Browse and hear all 69 scores
Get it free at launch
Recommended

MidiSlayer

$49.99

one-time · yours forever

  • ♪Bring your own sheet music: load any MusicXML and play it in time
  • ♪All 9 training modes and 3 arcade games, unlocked
  • ♪The full 69-piece library to play, not just hear
  • ♪Exam mode with per-skill ranks, built for ABRSM prep
  • ♪Runs on two of your machines (macOS, Windows, Linux). Free updates through v1

14-day money-back via Paddle, just email us · secure checkout · instant delivery

Studio

Per seat

teachers & schools

  • ♪The full app on every seat you buy
  • ♪Graded reading + exam mode, built for ABRSM
  • ♪Volume pricing, one invoice, no faff
Talk to us

How it works

  1. 1Download the free version for macOS, Windows or Linux. Use it as long as you like.
  2. 2Buy the full version when you're ready. Secure checkout by Paddle, pay by card.
  3. 3Your licence key arrives by email. No account required.
  4. 4Paste it into the app and everything unlocks. Activate once, then it works offline.

local taxes shown at checkout · sold direct through Paddle, our merchant of record · refunds handled by Paddle

Questions

Asked and answered.

For the full experience, yes. Any USB or Bluetooth MIDI keyboard works, from a £20 controller to a digital grand. No keyboard handy? The built-in on-screen keyboard is enough to try it out. The real thing wants real keys.

macOS (Apple Silicon and Intel), Windows 10/11 and Linux (.deb, .rpm and AppImage). Under the hood it's a lean desktop app with a native Rust core: MIDI timing comes off your hardware, your data lives in a local database, and after the one-time license activation nothing needs an internet connection.

Really. One payment and it's yours to keep, with every update through v1 included. No monthly fee, no expiry, nothing to lose access to. A tool you keep, not a treadmill you rent.

A lot. Note Flashcards in full, the Blitz arcade game, a free run of Cascade every day (the Daily Challenge), a jam session over the Pop Loop, the complete course on reading sheet music, and the whole score library to browse and listen to, with four pieces fully playable, one per shelf. Forever, with no card and no trial clock.

Especially for you. MidiSlayer ships with a built-in Learn course that takes you from "what is a staff" to reading your first notes, with real engraved examples, and it's in the free version. Every lesson ends right where the matching training mode begins.

Your key activates on up to two machines at once, any mix of Mac, Windows or Linux. Moving to a new machine is one click of "Deactivate on this device" in Settings, and support can free a slot if a dead machine took one with it.

Completely. Activate your license once and everything works without internet, forever: training, games, progress, all of it.

On your device, in a local database. No telemetry, no ads, and we don't sell your data. Your weak notes are between you and your piano.

Purchases are handled by Paddle, our merchant of record. Not working out? Email us within 14 days and we'll refund you. The free version exists so you can be sure before you buy.

Something else? Ask us directly. A human reads it, promise.