WEBMIDI.js makes it easy for a web developer or programmatically inclined musician to create Web applications that interact with its visitors’ MIDI devices. If you have ever tried to use the bare Web MIDI API to develop such applications, you certainly realized quickly how tedious it is to decrypt raw MIDI messages using binary arithmetic. Instead, WEBMIDI.js offers developers a plethora of semantically significant objects, properties, methods and events to work with. One cannot stress enough how significant this is for the future development of MIDI on the Web. WEBMIDI.js is the tool developers use to create the next wave of networked and socially engaging music sites and applications. And, developers like it. A lot. Even if it’s still a relatively niche tool, over 1100 developers starred it on GitHub, the reference for open-source software. Today, 919 projects rely on WEBMIDI.js, and this number keeps growing every day. The ability for the browser to easily interface with most electronic instruments made in the past 30 years offers significant opportunities to preserve, enhance or re-discover a rich musical and technical heritage. Including MIDI in the broader Web ecosystem also opens endless possibilities to create, teach, and distribute music in revolutionary new ways.