Loopstate — Free Browser-Based Modular Generative MIDI Sequencer

Loopstate is a free modular generative MIDI sequencer that runs entirely in the browser. Create complex polymetric patterns, arpeggios, euclidean rhythms, chord progressions, and generative sequences — then send them to any hardware synth or DAW via Web MIDI. No installation required. Built by bsidez.

10 Pattern Generators

• Arpeggiator — classic arp patterns with sync, swing, and ratchet
• Euclidean — mathematically distributed rhythms with rotation and gate control
• Rhythm — step-based drum and percussion patterns
• Melody — step-record melodic sequences with per-step velocity and gate
• Chord — chord progressions with triads, 7ths, clusters, quartal, and open voicings
• Canon — polyphonic canons with configurable follower intervals and delays
• Cellular — cellular automata-driven generative patterns
• Bounce — bouncing-ball physics rhythm generator
• MIDI File — import and loop standard MIDI files
• CC — continuous controller automation lanes

Sequencer Features

• Polymetric engine — each track runs at its own length, creating evolving polyrhythms
• 96 PPQN internal resolution — four times MIDI clock standard for precise timing
• Four pattern slots per track (A/B/C/D) with launch-quantized switching
• Transform chain: transpose, scale quantize, voicing expand, velocity, swing, humanize
• LFO per track routed to filter, volume, pan, pitch, or delay
• 102 musical scales from Western, Eastern, African, Middle Eastern, and experimental traditions
• Scenes — save and recall track play/mute/solo states with drag reordering
• Undo/redo for all pattern and transform changes
• Copy/paste patterns across tracks and slots
• Track duplication with full settings clone
• Solo and mute with keyboard shortcuts (S, M, Space, 1-9, A/B/C/D)

MIDI Output

• Real-time MIDI output via Web MIDI API — connect to any DAW or hardware synth
• Master clock with MIDI clock output (24 PPQN) and transport messages
• Slave mode — sync to external clock from Elektron, Roland, MPC, or any MIDI master
• Song Position Pointer (SPP) for pause/continue sync with hardware
• MIDI recording with CC capture and Format 1 MIDI file export
• MIDI Panic — All Notes Off + All Sound Off on all channels and ports
• Program Change support per track
• Per-port clock routing for multi-device setups

Use Cases

Live performance MIDI sequencing, hardware synth control, generative ambient composition, polymetric rhythm exploration, eurorack sequencing via USB-MIDI, music education, algorithmic composition, DAW MIDI input, and experimental sound design.

About

Loopstate is created by bsidez (Jeroen van Vliet). Free to use at loopstate.net.