Hi,
Disclaimer: I am the CTO of GetStream.io
Implementing what you describe is fairly simple indeed. First of all sign up on getstream.io and go to the dashboard. You will have an app with 4 different kind of feeds already configured.
to field. eg ({'actor': 'user:tom', 'verb': 'comment', 'object': 'nice work @john', to: ['notification:john']})We built a very simple example app with NodeJS and Mongoose, here you can find the interesting bits about the realtime UI code and here is how the main html page looks like.
I hope this helps, if not feel free to ping me at tommaso@getstream.io ;)
Best, Tommaso