I agree with cnp. I think it would've been much easier to grasp if the URLs worked like most APIs. For instance, I expected this URL https://samplechat.firebaseio-demo.com/users to return the users as JSON instead of the html data dashboard. This slowed me down more than anything when I started. I think it would be helpful to have both the data dashboard and the raw data, but on separate URLs. But generally it's awesome!