orDrumbox: Free Online Drum Machine & Step Sequencer

orDrumbox at a Glance

• Price: free of charge.
• License: open source, MIT license (source code on GitHub).
• Platform: any modern web browser with Web Audio API support, on Windows, macOS, Linux, ChromeOS, Android and iOS.
• Installation: none required; it can also be installed as a Progressive Web App (PWA) and used offline.
• Windows version: orDrumbox for Windows 0.1.0, a native program for Windows (x64), distributed as a ZIP file (download page).
• AI assistants (MCP): orDrumbox for Windows can be driven by an MCP client such as Claude Desktop or Claude Code (MCP guide).
• Sequencing: multi-track step sequencer with per-track loop points, polyrhythms, Euclidean fills, swing, conditional triggers and probabilities.
• Sound: drumkits, custom sample import and a synthesizer with three oscillators, FM, filter, noise, ADSR envelope and two LFOs.
• Export: WAV audio and standard MIDI files; patterns, songs and drumkits as JSON.

What Is orDrumbox?

orDrumbox-v2 combines a step sequencer, rhythm-generation tools, sample-based drum tracks and a software synthesizer. It can be used to create patterns for House, Techno, Hip-Hop, Rock, Chiptune and experimental music.

Multi-Track Step Sequencer

Each track of a pattern has its own notes and settings, so tracks with different rhythms and lengths play together.

• Pattern editing: add, remove and edit notes on the sequencer grid or in the piano roll.
• Per-track loop points: each track loops over its own length.
• Polyrhythms: tracks of different lengths shift against each other from one loop to the next.
• Euclidean fill and retrigger: add evenly spaced sub-hits or repeated hits to a note.
• Swing: per-track delay of odd-numbered steps.
• Triggers and probability: a note can play every N-th loop, with a phase offset, or with a given probability.
• Note and track controls: velocity, pitch and stereo panning per note; volume, pitch, pan, decay and filter per track, with LFO modulation.

Automatic Generation

orDrumbox can generate parts of a pattern and vary them over time. Generated notes can then be edited like any other note.

• Drum, Bass and Chords buttons: generate the corresponding parts from a genre-based song structure.
• Auto: regenerates a track at each loop while the other tracks stay unchanged.
• Variation: adds ghost notes or doubled notes, removes notes, and changes velocity or pitch at random at each loop.

Software Synthesizer

Any track can play a sound generated by the built-in synthesizer instead of a sample. The synthesizer includes:

• Three oscillators (sine, triangle, sawtooth, square) with octave and detune.
• FM synthesis with five routing algorithms.
• A resonant filter (low-pass, high-pass, band-pass, notch) with envelope modulation.
• A white noise generator with its own filter.
• An ADSR envelope and a glide (slide) setting.
• Two LFOs, free-running or synced to the tempo.
• Built-in and user presets.

Drumkits and Audio Samples

orDrumbox includes several drumkits and demo patterns. The sounds cover acoustic drums and percussion, vintage drum-machine sounds, electronic drums and 8-bit sounds.

Audio files (WAV, FLAC, MP3, AAC) can be added to a kit, and a folder of samples can be imported as a new drumkit; each sample's gain, tuning, decay and instrument can then be adjusted.

Effects and Mixing

• Per track: filter, saturation (soft, hard, tape), reverb (room, hall, plate, spring, gated) and delay (slap, tape, ping-pong).
• Master bus: pre-gain, compressor, low-cut and high-cut filters, master volume and a spectrum analyzer.

Saving and Exporting

Patterns, songs and drumkits are stored in the browser and can be exported as JSON files. Audio export renders a pattern as a WAV file for playback, sharing or further processing in a digital audio workstation (DAW). MIDI export creates a standard multi-track MIDI file, and MIDI files can be imported into new patterns.

MIDI Devices

In browsers that support Web MIDI, orDrumbox can send notes to a MIDI output device and follow an external MIDI clock.

Browser Compatibility and Supported Devices

orDrumbox runs in a modern web browser that supports the Web Audio API, on Windows, macOS, Linux, ChromeOS, Android and iOS. An internet connection is required for the first load; once installed as a PWA, it works offline. On screens up to 768 px wide, a bottom tab bar replaces part of the toolbar. Performance depends on the device.