Webix Remote Server

I’m using Webix Jet and trying to use their remote server side requests, as an alternative to REST (https://docs.webix.com/desktop__webix_remote_php.html), but I have no idea how to implement this with Slim 3.

Is there a way to pass classes and/or methods to the application layer itself. I’ve tried every Middleware possible - https://www.slimframework.com/docs/v3/concepts/middleware.html#invokable-class-middleware-example

Any help would be greatly appreciated.