When I started work on version 1 of Polychord for iPad (almost 10 years ago, wow!) MIDI wasn’t available yet on iOS as a public framework. I decided to use the

When I started work on version 1 of Polychord for iPad (almost 10 years ago, wow!) MIDI wasn’t available yet on iOS as a public framework. I decided to use the MIDI format for the underlying synth I built, regardless. It made sense because it was already a solved problem, and was well-suited to a resource constrained environment. In the end it was maybe the most impactful decision I made, as MIDI flourished and Polychord found a niche as a controller. Inter-app MIDI became one of the first ways in which iOS apps could work together rather than being little islands unto themselves, which then led to Audiobus, which led Apple themselves to open the door to cross-app features on the platform. It may be a dated standard, but a standard nonetheless; and that’s valuable in ways that are hard to quantify. Hacking on top of MIDI is not always easy, but it can be gratifying. You also discover fun Easter eggs — like the names of defunct manufacturers buried in the data bytes of the spec.