By "online", of course you want the online system for dice, as others have said, I think Roll20 is good, and for chat systems skype or Discord is fine (last time I checked Roll20's online video/chat is wonky to get working right).
But do you also mean playing with random people online? Or friends that you know?
I'd suggest starting simple. A full on character creator is going to be tough, but a reference app such as you see in other systems would not only be useful, but feasible given the fact that Eclipse Phase is released with a Creative Commons license.
This reminds me of a small scene in The Murderbot Diaries (which everyone should read tbh, they're on Amazon. I imagine if you like Eclipse Phase you'd probably like them).
The protagonist has a bunch of little micro surveillance drones that he's flying around, like fingernail sized things (as I interpreted it anyway) and he gets shot at by someone with an energy weapon. The drones all detect this and (a) try to get in the way of the laser shots, and (b) try hit the person shooting in the face.
You may actually want to try to find a copy of the book "A Time of War" which is the newer version of the Mechwarrior roleplaying game. Could be easier to mash with EP.
Link (Amazon): http://www.amazon.com/Battletech-Time-Catalyst-Games-Labs/dp/1934857653