WebMIDI Sysex Editor Framework

While originally intended to be a web-based parameter editor for Yamaha MONTAGE M, inspired by the PGX Controllers shown at SUPERBOOTH 2025, this project has developed into a general-purpose framework for quickly and easily creating intuitive parameter editing interfaces for any device with documented sysex parameters.

Interfaces are built with lightweight HTML, and the application handles everything else.

The framework supports per-device and per-engine MIDI CC mapping to any sysex parameter, auto-updating human-readable parameter values, a flexible and scaleable graphical user interface with a joyful envelope editor, and patch memory for devices that have none.

The system also provides a means for a WebMIDI-equipped device to act as a relay for remote devices that lack WebMIDI support, or are not physically connected to the MIDI device.

This framework makes building one-control-per-function editors for synthesizers and other MIDI devices as simple as laying out controls in an HTML layout. The system removes any need for the interface designer to know anything more than the names of the parameters they wish to control.

Once the sysex parameters for a particular device are gathered and stored, a control can be added with a simple set of HTML tags. For example:

Cutoff

… is enough to present a graphical representation of a knob, which will send and receive the appropriate sysex parameters within the ranges defined by the parameter, and give the user the human-readable version of the current value in cases where a simple 0-127 type of value is unintuitive, such as the waveform being used by an LFO.

Furthermore, the system can implement a secure link between a host computer connected via WebMIDI to the MIDI device, and any number of remote devices such as iPads, which can remote-control the MIDI device regardless of WebMIDI support.

Having built the framework with the MONTAGE M in mind, I was able to produce additional editors for Yamaha MONTAGE / MODX / MODX+ and reface CS in a matter of hours.

The video linked in the submission represents my complete presentation of this technology.

This framework has not yet been made public, but I am inspired by the fact that it makes sound design on my exceptionally-complex synthesizers a delightful experience, without menu diving or having to use complex shift-functions.