GGPO is a networking library that game developers can use to add networked gameplay support to arcade style games. GGPO's latency hiding techniques give each player a gameplay experience that is nearly indistinguishable from playing with their friends locally, even against players around the world.

GGPO uses a peer-to-peer topology to run a complete copy of your game for each player, transmitting controller inputs over the network to keep these copies in sync. Each player's inputs are sent to their copy of the game without having to wait for their opponent's to arrive over the network.

If the simulations diverge, GGPO rolls back to the most recent accurate state, corrects the mistake, and jumps back to the current frame, all before the player can notice. This provides the illusion of lag-free gameplay.

Thousands of gamers are already using GGPO to play classic, old school fighting games against opponents around the world. GGPO's latency hiding techniques maintain the illusion of lag-free gameplay even during intercontinental play.

I started working on GGPO several years ago to find a way to play fighting games at a very high skill level, in spite of internet latencies. I'm a moderator for Shoryuken.com, a co-owner and the Tournament Director for the Evolution Championship Series fighting game tournaments, and an engineer employed at VMware.