mpump 1.3.10

MIDI sequencer for USB hardware — runs in the browser or from the command line

mpump

Hot-plug MIDI sequencer for USB hardware
Browser, TUI, or command line — no setup required

https://gdamdam.github.io/mpump/

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Open the browser app, connect a USB MIDI device, and it starts playing immediately. 50 devices recognized automatically, 610+ patterns across 15 genres, live step-grid editing. No install required — runs entirely in the browser via Web MIDI.

For deeper hardware control on Mac, the Python package adds a terminal UI, a headless CLI, and a local web server with multi-client sync. Devices hot-plug cleanly: connect and disconnect hardware mid-set with bar-locked transitions.

Table of Contents

• Install
• Interfaces
  • Browser Sequencer (standalone)
  • Web UI (Mac + Python)
  • Terminal UI
  • Headless CLI
• Supported Devices
• CLI Reference
• Pattern Library
• Sync Model
• How Slides Work
• Project Layout
• Tested On
• Contributing
• License

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Install

pip install mpump

Requires Python 3.11+ and macOS (CoreMIDI). All supported devices are USB class-compliant — no extra drivers needed.

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Interfaces

Browser Sequencer (standalone)

Open the hosted app in Chrome, Edge, or Opera — no install, no server, no Mac required. The sequencer runs entirely in the browser using the Web MIDI API. Connect your MIDI devices via USB, grant MIDI permission, and play.

Firefox works with a Web MIDI add-on. Safari and iOS are not supported (no Web MIDI).

Features: auto-detection of 50 USB MIDI devices, live step-grid visualization, genre/pattern/key/octave switching, tap-to-edit patterns, shuffle button to randomize genre + pattern globally or per-device, save edited patterns to the EXTRAS genre.

To build and serve locally:

cd mpump/server
python3 scripts/export_patterns.py
npm install && npm run build
npm run preview

Deploy mpump/server/dist/ to any HTTPS host (GitHub Pages, Netlify, Vercel) for zero-install access from any computer with USB MIDI.

Web UI (Mac + Python)

mpump-web

Opens a web server on port 8080. Point any browser on the local network at http://<your-mac-ip>:8080 — works great from iOS Safari. Supports Add-to-Home-Screen for a full-screen PWA experience.

Features: live step-grid visualization, genre/pattern/key/octave switching, tap-to-edit patterns, save edited patterns to the EXTRAS genre. Multiple browser clients can connect simultaneously.

Terminal UI

mpump-ui

Three-panel TUI showing S-1, T-8 and J-6 side by side. Browse and commit patterns live.

Headless CLI

mpump --cli

Starts immediately with the given flags, no UI.

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Supported Devices

The browser sequencer auto-detects 50 USB MIDI devices. Devices are recognized by their USB MIDI port name and start playing automatically when plugged in.

Roland

Device	Type	Mode	Status
S-1	AIRA Compact monosynth	synth	Tested
T-8	AIRA Compact drum machine	drums+bass	Tested
J-6	AIRA Compact chord synth	synth	Tested
SP-404MK2	Sampler	synth	Untested
TR-6S	Drum machine	drums	Untested
TR-8S	Drum machine	drums	Untested
MC-101	Groovebox	drums+bass	Untested
MC-707	Groovebox	drums+bass	Untested
SH-4d	Polysynth	synth	Untested
TB-3	Bass synth (303-style)	synth	Untested
TB-03	Bass synth (303 clone, Boutique)	synth	Untested
JD-Xi	Crossover synth	synth	Untested
JU-06A	Juno clone (Boutique)	synth	Untested
SE-02	Analog mono (Boutique)	synth	Untested
GAIA 2	Wavetable/VA polysynth	synth	Untested

Korg

Device	Type	Mode	Status
minilogue xd	4-voice analog poly	synth	Untested
minilogue	4-voice analog poly	synth	Untested
monologue	Analog monosynth	synth	Untested
NTS-1	Programmable synth	synth	Untested
drumlogue	Hybrid drum machine	drums+bass	Untested
wavestate	Wave sequencing synth	synth	Untested
opsix	FM synth	synth	Untested
modwave	Wavetable synth	synth	Untested

Novation

Device	Type	Mode	Status
Circuit Tracks	Groovebox	drums+bass	Untested
Circuit Rhythm	Sample groovebox	drums	Untested
Bass Station II	Analog monosynth	synth	Untested
Peak	8-voice hybrid poly	synth	Untested

Arturia

Device	Type	Mode	Status
MicroFreak	Digital/hybrid synth	synth	Untested
DrumBrute Impact	Analog drum machine	drums	Untested

Behringer

Device	Type	Mode	Status
TD-3	303 clone	synth	Untested
RD-6	606 clone	drums	Untested
Crave	Semi-modular mono	synth	Untested
Model D	Minimoog clone	synth	Untested
Neutron	Semi-modular	synth	Untested
Poly D	4-voice analog poly	synth	Untested
K-2	MS-20 clone	synth	Untested
MS-1	SH-101 clone	synth	Untested
DeepMind 12	12-voice analog poly	synth	Untested
Wasp Deluxe	EDP Wasp clone	synth	Untested

Elektron

Device	Type	Mode	Status
Syntakt	Drum machine + synth	drums	Untested
Digitakt	Sampler / drums	drums	Untested
Model:Cycles	FM groovebox	drums+bass	Untested
Model:Samples	Sample groovebox	drums	Untested
Analog Rytm MKII	Analog drums + sampler	drums	Untested
Analog Four MKII	4-voice analog poly	synth	Untested

Other

Device	Type	Mode	Status
TE OP-Z	Multi-track synth	synth	Untested
TE EP-133 K.O. II	Sampler / drums	drums+bass	Untested
Sequential Take 5	5-voice analog poly	synth	Untested
IK UNO Drum	Analog/PCM drum machine	drums	Untested
IK UNO Synth	Analog monosynth	synth	Untested

Tested = verified with hardware. Untested = port names may need adjustment; please report issues.

All 50 devices are supported across all interfaces. The TUI shows dedicated panels for S-1, T-8, and J-6; other devices are auto-detected and sequenced in CLI and web modes.

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CLI Reference

mpump-web

mpump-web                     # defaults: BPM 120, port 8080
mpump-web --bpm 133           # custom tempo
mpump-web --port 9000         # custom port

Flag	Default	Description
--bpm N	120	Initial tempo (20-300)
--port N	8080	HTTP port to listen on

Pattern editing

Tap any step in the grid to toggle it on/off. Long-press (or right-click) a step to open the detail editor where you can adjust semitone offset, velocity, and slide. Edited patterns can be saved to the EXTRAS genre, which persists across sessions in ~/.mpump/extras.json and is available in all three interfaces.

mpump-ui

mpump-ui                                        # defaults
mpump-ui --bpm 133 --genre acid-techno --pattern 3
mpump-ui --t8-genre dub-techno --t8-pattern 5 --t8-bass-pattern 2
mpump-ui --j6-genre trance --j6-pattern 4

Key bindings

Key	Action
Tab	Cycle focus: S-1 -> T-8 -> J-6
<- / ->	Previous / next genre
up / down	Previous / next pattern
Enter	Commit browsed pattern/genre to device
b / B	T-8 bass pattern down / up (browse only)
k / K	Root key down / up (immediate, S-1 and T-8)
o / O	Octave down / up (immediate, S-1 and T-8)
Space	Pause / resume focused device
= / -	BPM +5 / -5
q	Quit

Browse with arrow keys (and b/B for bass) then press Enter to apply. The now-playing strip always shows what is actually running.

mpump (headless CLI)

General

Flag	Default	Description
--bpm N	120	Tempo (20-300)
--list	—	Print all synth patterns and exit
--list-drums	—	Print all drum patterns and exit
--list-bass	—	Print all bass patterns and exit
--list-j6	—	Print all J-6 chord patterns and exit
--list-devices	—	Print all 50 supported devices and exit

S-1

Flag	Default	Description
--genre GENRE	techno	S-1 genre — see GENRES.md for full list
--pattern N	1	Pattern 1-10 within genre
--key KEY	A	Root key: A A# Bb B C C# Db D D# Eb E F F# Gb G G# Ab
--octave N	2	Root octave 0-6 (A2 = MIDI 45)

T-8

Flag	Default	Description
--t8-genre GENRE	techno	Drum/bass genre
--t8-pattern N	1	Drum pattern 1-10
--t8-bass-genre GENRE	same as --t8-genre	Bass genre, independent of drums
--t8-bass-pattern N	1	Bass pattern 1-10, independent of drums
--t8-key KEY	A	Root key for bass
--t8-octave N	2	Root octave for bass

J-6

Flag	Default	Description
--j6-genre GENRE	techno	Chord genre — see GENRES.md for full list
--j6-pattern N	1	Chord pattern 1-10

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Pattern Library

Full pattern catalogue with names and descriptions: GENRES.md

S-1 — 160 melodic patterns

15 genres (acid-techno has 20, rest have 10). All patterns are expressed as semitone offsets from the root, so --key and --octave transpose them freely. All synth-mode devices in the browser sequencer share these patterns.

mpump --list           # full catalogue with descriptions

T-8 — 150 drum + 150 bass patterns

15 genres x 10 each. Drum and bass patterns are selected independently. All drums-mode and drums+bass-mode devices in the browser sequencer share these patterns.

mpump --list-drums     # drum patterns
mpump --list-bass      # bass patterns

J-6 — 150 chord progressions

15 genres x 10. Root is always C (MIDI 60). On connect, mpump sends a Program Change to auto-select the matching chord set on the J-6.

mpump --list-j6

EXTRAS — user-created patterns

Patterns edited and saved via the web UI or TUI are stored in ~/.mpump/extras.json and appear as the extras genre in all interfaces. In the browser sequencer, extras are stored in localStorage and are independent of the file-based extras.

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Sync Model

All devices share a single step-grid anchored to a global t0. Every sequencer starts at the next bar boundary (16 steps from t0), so:

• Devices that connect at different times are always phase-locked within one bar
• Pattern changes and pause/resume introduce at most one bar of delay, then re-enter on the beat
• BPM changes reset t0 and batch-restart all devices at the same boundary

MIDI clock (24 PPQN) is sent to devices that support it for BPM-synced effects (LFO, delay, arpeggiator). No MIDI Start/Stop messages are sent, so the devices' internal sequencers are not triggered.

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How Slides Work

On acid patterns, steps marked slide=True send the next note_on before the previous note_off. On a monosynth like the S-1 or TD-3, this triggers legato / portamento if portamento is enabled on the device.

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Project Layout

pyproject.toml
mpump/
  __init__.py       # package version
  cli.py            # mpump entry point (headless + TUI)
  ui.py             # Textual TUI application
  scanner.py        # hot-plug: polls MIDI ports every 0.5 s, spawns threads
  sequencer.py      # per-device step-loop threads (Sequencer + T8Sequencer)
  devices.py        # device profiles (port names, channels, config)
  patterns.py       # S-1: 160 melodic patterns (15 genres)
  patterns_t8.py    # T-8: 150 drum + 150 bass patterns
  patterns_j6.py    # J-6: 150 chord progressions
  extras.py         # user-created patterns (~/.mpump/extras.json)
  keys.py           # key name -> root MIDI note mapping
  web/
    engine.py       # WebEngine: async state manager wrapping DeviceScanner
    server.py       # FastAPI + WebSocket + static SPA serving
  frontend/
    src/             # React + TypeScript SPA (Vite, served by mpump-web)
    dist/            # built output
  server/
    scripts/         # export_patterns.py — Python -> JSON converter
    src/             # React + TypeScript standalone SPA (Web MIDI, 50 devices)
    public/data/     # generated pattern JSON files
    dist/            # built output — deploy to any HTTPS host

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Tested On

• macOS Sequoia 15, Python 3.11
• Roland S-1, T-8, J-6 (hot-plug + playback confirmed)
• Roland SP-404MK2 (hot-plug confirmed; pattern playback not yet hardware-tested)
• Browser sequencer: all 50 devices in registry (port names for non-Roland devices need hardware verification)

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Contributing

1. Fork the repo and create a feature branch
2. Make your changes and ensure tests pass: pytest
3. Submit a pull request

Bug reports and device compatibility feedback are welcome — please open an issue.

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License

GPL-2.0