still working on https://stringscales.com - fun sideproject to visualize guitar scales on a configurable fretboard, with interactive note highlighting to a backingtrack.
The backingtrack is what I'm actively improving right now. It's just a pad running now, but it will turn into a full track with bass/drums/piano/... and will feature a comprehensive chords based editor so you can add and save your own progressions with a logged in account.
Does it let you visualise quarter tone fretting? (Or is it just me who's obsessed with Angine de Poitrine right now?)
that would certainly be a very interesting thing to add, but in the current iteration that is not possible.
The biggest issue here is that there's not really "one" microtonal system out there. The entire fretboard of a conventional guitar is mapped to work in 12tet - and the libraries I'm using to do all the musical operations also only supports 12tet.
to accommodate all the microtonal temperaments out there would be a pretty daunting task. But I'm not saying never!