midi.js
A JavaScript library for creating MIDI applications in the browser with soundfont support and audio effects.
What is midi.js?
MIDI.js is a JavaScript library that enables developers to create MIDI-powered web applications. It solves the problem of complex audio programming by providing tools to load soundfonts, play MIDI files, apply audio effects, and synchronize multiple instruments directly in the browser.
Web developers and creative coders building interactive music applications, audio-visual experiments, or educational tools that require MIDI playback and synthesis in the browser.
Developers choose MIDI.js because it bundles essential MIDI functionality—like soundfont support, precise timing, and audio effects—into a single library, reducing the need to integrate multiple low-level Web Audio API components manually.
Overview
:musical_keyboard: Making life easy to create a MIDI-app on the web. Includes a library to program synesthesia into your app for memory recognition or for creating trippy effects. Convert soundfonts for Guitar, Bass, Drums, ect. into code that can be read by the browser. Supports multiple simultaneous instruments and perfect timing.
Use Cases
Best For
- Building web-based piano or instrument simulators
- Creating interactive music visualizers with note-to-color mapping
- Developing educational tools for music theory or ear training
- Parsing and playing standard MIDI files in a web application
- Adding real-time audio effects (e.g., chorus, delay) to browser-based music apps
- Experimenting with synesthesia by linking sound to visual elements
Not Ideal For
- Projects requiring real-time MIDI input recording from hardware devices, as MIDI.js is optimized for playback and synthesis rather than capture.
- Applications needing custom audio synthesis beyond pre-rendered soundfonts, since it relies on static soundfont files for instrument sounds.
- Teams prioritizing modern, lightweight libraries without legacy dependencies like Flash fallbacks, which are deprecated and may not work on newer systems.
- Use cases where fast load times are critical, due to the large file sizes of soundfonts that must be downloaded or generated.
Pros & Cons
Pros
MIDI.js converts instrument soundfonts into browser-playable code, as shown in the MIDI.loadPlugin API that allows loading multiple instruments like acoustic_grand_piano and acoustic_guitar_nylon from pre-rendered or custom sources.
It provides a full MIDI player with functions for play, pause, stop, and timing adjustments, demonstrated in MIDI.Player.js with methods like loadFile, start, and resume for handling standard MIDI files.
Integrates Tuna.js for a wide range of effects including MoogFilter, Bitcrusher, and Phaser, with configurable parameters detailed in the README for real-time sound manipulation.
Supports multiple audio APIs including Web MIDI, Web Audio, HTML5 Audio, and Flash fallbacks, ensuring functionality across different browsers as mentioned in the key features.
Cons
Generating and loading custom soundfonts requires additional tools like NodeJS or Ruby packages, which adds complexity and extra steps compared to plug-and-play audio libraries.
The README focuses on playback and effects, with no built-in API for recording MIDI input or handling real-time data from external devices, limiting interactive applications.
Relies on legacy technologies like Flash for fallbacks and older libraries such as Tuna.js, which may not be actively maintained and could introduce compatibility issues in modern browsers.
Frequently Asked Questions
Related Projects
Howler.jsJavascript audio library for the modern web.
LibrosaPython library for audio and music analysis
audioFluxA library for audio and music analysis, feature extraction.
audio.jsA cross-browser javascript wrapper for the html5 audio tag
Found a gem we're missing?
Open-Awesome is built by the community, for the community. Submit a project, suggest an awesome list, or help improve the catalog on GitHub.