Java (web-based)
Based on Project Darkstar (PDS), which is an advanced game server written in Java. This game server runs on the TileGamer.com server, and keeps all game players in any given game process synchronized. Communicates with the game clients in the form of XML files sent back and forth.
Python (XO-based)
Each XO Laptop user involved in a given game process communicates with each of the other players via the Python game server, which is hosted locally and keeps all game players synchronized. Communicates with the other game servers in the form of XML files sent back and forth using the wireless peer-to-peer networking.