No central server
There is no machine that has to be up for your world to work. Trackers and relays hold no authority: the most a hostile one can do is hide a peer from you.
The world is split into 8×8-chunk regions, and a small committee of player-run machines simulates and re-checks each one. Any player shares a world straight from the pause menu.
Alpha — 66 open or retiring limitations, each with the test that retires it.
There is no machine that has to be up for your world to work. Trackers and relays hold no authority: the most a hostile one can do is hide a peer from you.
Each 8×8-chunk region is simulated by one peer and re-executed by the others in its committee. A batch commits only with a quorum, so no single machine — including the one that made the world — decides on its own what happened.
A headless worker keeps your node on the network with Minecraft closed. In a live test, a world whose host was killed was re-hosted by another peer from the network in about three seconds.