@Christoph-Hart don't know if this is helpful or how hard it would be to implement in HISE/C++ side, but, since you never got this running in linux: as an alternative to using websockets (and this would be my preferred way of communication if it were possible), you could potentially ust mqtt for communication. That's what I've done with a pretty large electron sound design app I made, and it works great for ipc and communication. (plus it's more reliable, faster, and cleaner because you have topic based message routing).
Basically main process just spins up an mqtt broker on launch, and then all my different webviews, and swift audio rendering processes, just connect to the main broker and use that for pub sub. Disadvantage would be people would have to include a lib like https://github.com/mqttjs in their webview, but it looks like you need to add a little code already anyways to get the comms working.
