You can use this nodejs server script for the hotkey API, if hosting it yourself.
You can specify your URL via the index.html file; (v21.2 and up) , or somewhere in the lib.js file.
session.apiserver = "wss://api.vdo.ninja:443";
Valid SSL encryption is required.
Please note: Help with self hosting the hotkey api is not supported beyond what is already offered here. You're on your own if you attempt it.