momo's front-page landscape at night: a starry sky with moon and planets over a flat plain with small trees, a glowing pond and a white turtle.

MOMO

103
Music Education
Creative Coding
Web App
Creative Coding
Creative Coding
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INTRO

momo is a browser-based music, coding and creative playground for children from about three to ten years old. Children play a real drum kit or keyboard against falling notes, sing, build beats and loops, draw with sound, and write small programs that react to their own playing. It runs entirely in the browser, needs nothing installed, and lets a four-year-old and an eight-year-old share one screen and the same instruments while each gets an interface built for them.

momo is currently in development. Access to the app is by invitation — please get in touch at info@mojari.de to request access.

momo grew out of Spielwerk, a small music and coding playground, into an open-source learning environment (AGPL-3.0). Its method is research through making: every game, lesson and rule is written down with the evidence it rests on, tested in play, and revised.

Key facts

Ages 3–10, levels set per child, never by age

Runs in the browser, nothing to install, no account

Open source (AGPL-3.0)

What we invented

Difficulty is derived, not authored. A song is charted once at full detail; five playable difficulties are generated from that chart by rule. That is what lets two children of different ages play the same song at the same time, each on their own screen.

Mixed-age play instead of a difficulty slider. Younger and older children get different roles in one shared game: one builds a loop while the other solos over it, or one child's drum hits drive the other's small program. Each child is scored against their own screen, never against the other.

A melody engine that never repeats. Practice phrases are generated from chord progressions, scales and rhythm cells that are common musical property, checked against the last 32 phrases so they do not repeat, and woven into one growing song the child can keep, save or replay.

A feedback guard for a live microphone in a living room. Three published feedback-detection tests with a persistence vote notch out howling frequencies automatically and tell a held sung note apart from a feedback loop.

Video sync by tapping. A chart can be lined up with a performance video by tapping the first word and the beat; the app never analyses the video's own audio.

Learning analytics on the device only. Every stored measurement must answer one of 13 explicit learning questions; anything else is never recorded. A parent can choose to export an anonymous weekly summary for research — nothing is sent automatically.

Standards

momo keeps a catalogue of numbered design rules, each with its public source and a note on how far the app meets it. It is built against:

  • Accessibility: WCAG 2.2 as working reference (target sizes, no-drag alternatives, flash limits, reduced motion, contrast, keyboard use, labelled icons).

  • Children's privacy: the UK Age Appropriate Design Code as baseline; GDPR data minimisation and the German TDDDG for device storage; COPPA used as a checklist.

  • Content and sound safety: designed for the lowest USK/PEGI band; output limiters and safe-listening defaults following WHO-ITU H.870.

  • Open formats and licences: songs in an open JSON chart format; public-domain or Creative Commons music with every source recorded.

The same front page at dusk; the sky and trees follow the real time of day.
The same front page at dusk; the sky and trees follow the real time of day.
The same loop as a grid of coloured cells with note names.
The same loop as a grid of coloured cells with note names.
momo on a phone: front page and player picker.
momo on a phone: front page and player picker.
Spielwerk home screen with an animal avatar, the next lesson and game tiles such as Falling Lanes, Echo and Sound Painter.
Spielwerk home screen with an animal avatar, the next lesson and game tiles such as Falling Lanes, Echo and Sound Painter.
The front page by day, in turquoise.
The front page by day, in turquoise.
Parents page: what momo is, how to use it with children and what happens to data.
Parents page: what momo is, how to use it with children and what happens to data.
"Make a Loop" in ring view: each ring is an instrument, the dots are beats.
"Make a Loop" in ring view: each ring is an instrument, the dots are beats.
Security and privacy

  • Local-first. Profiles, settings, recordings and songs stay in the browser on the device that is used. There is no server-side account and no backend that stores personal data.

  • No accounts, no passwords, no tracking. A profile is a local choice of animal and name, not a login. No advertising, no third-party analytics, no third-party code loaded at runtime.

  • Microphone and camera are read live, never recorded. Nothing is stored, streamed or uploaded.

  • Anything that leaves the device is an adult's explicit choice — and contains no names or device identifiers.

Education and parents

Learning. momo follows the order that Orff, Kodály, Dalcroze, Suzuki and Gordon agree on: sound before symbol, body and voice before the instrument, imitation before reading. Its lesson path runs through pulse, rhythm, pitch, keyboard, reading and band skills before notation appears. There is no fail state, no grades and no ranking; feedback describes what was played, not the child. The curriculum cross-references German primary-school music plans, so home play connects with school lessons.

For parents. Nothing to install, no account, no ads, no in-app purchases, no chat, no virtual currency. Links that lead outside the app sit behind a short grown-up gate, and the first use of a microphone or camera is explained in plain language before the browser asks for permission.

CREDITS

Concept, research and development: Moritz Richartz