how to connect non unity app to webgl

Hi!

Any ideas from you guys how I could set up an easy way for a any client to connect to a unity webgl application via websocket / HLAPI?

Any other ways to do this easily? Any recommendations?


Scenario:

1. Non unity app button click (or webserver redirect to Unity WebGL player)
   
2. Open browser with embedded Unity WebGL app
3. Send data to Unity