Yes, you can have an internet device ping the Envoy for data, but it's still not real-time. It's five minute increment posts at best. And then that's actually an average of the power over that amount of time.
It all depends on what you are doing. If you want to track data, or if what the sun was doing 5 or 15 minutes ago is good enough for your application, then yes, pinging the Envoy through API works great.
Frankly, about the only thing I know about API is that it's a way to get data somewhere else. Still, I did manage to stumble my way through the settings to pull data from the Envoy and post it to PVOutput.org. I need to play around with that some more.
https://pvoutput.org/intraday.jsp?sid=60383
I would be fun to have just a giant display to put on your wall which simply shows how much solar power you are making right now. Seems totally doable with a micro-controller and wireless.