I assume he means that node + nginx runs the game at the HTTP level but the actual game engine and logic are in Java.

But wouldn't the game just be connected straight to Java over websocket once the client has been paired to the server?

From the looks of it I don't think they are using Node for anything related to the game itself. At best it might be used to pair a client to a server but that's basically nothing.

Not really sure, perhaps the game itself isn't web-aware and they just use node.js to pull messages in and out because it is fast?

Will have to see if Ivan replies to know for sure. :)

Game is connected to Java over websocket through haproxy. I'm going to remove haproxy as soon as i discover solution for a few backend problems.

Ah, that's pretty much what I expected. So Node has nothing to do with how nice it's running.

One more question if you don't mind: Are you doing any server side checks to make sure player movement is within bounds and then doing prediction on the client?