I was planning to use socket.io with the same stack (Python, Flask) for a game development project last year. Figured that the Python ports of socket.io weren't well-maintained so I took the traditional approach with Comet(Long-polling). On another note, if you're interested in Socket.IO because of WebSockets then do know that Android 4.3 and older don't support WebSockets and so the server might need to support Long-polling anyway. It might actually introduce more lag to first check for websockets, and if unavailable, fall back to long-polling. I will wait till majority of target devices support it by default.