A server on Starblast.io, is the same thing as a system. Systems are rooms where about 30 players can play. There can be more or less than 30 players, depending on the game mode. In team mode it can go up to 60, survival 50, invasion 6, and PDM can have up to 20. During the ACW events there can be up to 200+ in the game because it is held on a special servers to take more people.