Most MPE tools try to do everything at once: visualise, analyse, record, monitor. MPE Keys, released on 10 September 2026 by developer Christophe Kalkau, goes the other way. It takes three modules out of the larger MPE Insight workspace — the keyboard, the two wheels and the Grand Staff — and ships them as a small standalone app that does nothing else.
At €14.99 EUR / $12.99 USD for Windows and macOS, it is aimed squarely at players who want to see what their controller is doing without running a full performance environment alongside their DAW.
What it actually shows
The core of MPE Keys is a drawn keyboard that responds to live MIDI input. You pick a key range — 88, 61, 49 or 25 keys — and the app scales accordingly. The developer's reasoning here is practical rather than aesthetic: a smaller range means bigger keys, which is what a small laptop screen and a 25-key controller both want anyway.
Alongside the keyboard sits the Grand Staff, which is the more interesting half of the app for anyone coming from a notated background. It renders what you play across treble and bass clef in the key signature you choose, and — critically for MPE — draws per-note pitch bend as a curve extending from each notehead. That single detail turns a notation view into an expression view: a slide you played on a Seaboard or a Continuum stops being an abstract stream of channel pitch-bend messages and becomes a visible line on the staff.
There are five display modes for that data: the notes currently held, a scrolling timeline, expressive ribbons, a harmonic field, and guitar tablature.
Features worth knowing about
A few things go beyond visualisation:
- MIDI in and out. MPE Keys has a dedicated output port, so notes you trigger with the mouse or computer keyboard pass through to your synth. It sits in the signal path rather than beside it.
- MIDI file playback. Load a
.midfile and it plays through the same path as live input, with full transport control — useful for reviewing a take you recorded elsewhere. - Record and export. Capture a performance and write it out as a standard
.mid, as CSV if you want to read the raw numbers, or as a printable notation sheet. - Stage view. Shift or F11 strips away toolbars, frames and titles, and hides the cursor after two seconds. This is clearly built for people projecting the display during a performance.
- Transparent background. Drops the panel chrome entirely so only the keys render — handy for compositing over video in a streaming or tutorial setup.
- Presets, snapshots and MIDI Learn. Two presets per design as a starting point, your own saved looks alongside them, and the ability to map a hardware knob to a control so your hands stay on the instrument.
Where this fits with MPE Insight
Kalkau has been explicit that MPE Keys is not a replacement. MPE Insight remains unchanged and keeps all nine of its modules. MPE Keys is described as the focused version for people who want the keyboard and notation tools without the rest of the workspace.
More interestingly, the developer frames the keyboard work done here as groundwork for MPE Insight 3.0, announced as coming soon. The teased features include lighting that sits in the key bed with each black key casting its own shadow, and a microtonal design where keys split into quarter-tone terraces with a just intonation tuning beside it — and a hardware bend still gliding continuously through those steps. That last point matters: microtonal display that respects continuous pitch rather than quantising it is not something most MIDI monitors attempt.
Why visualisation tools keep appearing
There is a reason this category is growing. MPE generates far more data than standard MIDI — per-note pitch bend, channel pressure and CC74 timbre, all flowing simultaneously across a channel zone — and almost none of it is visible in a typical DAW piano roll until after you have recorded it. Players learning a Seaboard, an Osmose or a Continuum are often working blind, unsure whether an unwanted wobble comes from their hand, the controller's sensitivity curve or the receiving instrument's bend range.
A tool that draws pressure and bend in real time collapses that guesswork. Whether it needs to cost more than a coffee is exactly the question MPE Keys is answering.
More information and downloads: Christophe Kalkau — MPE Keys