Tutorial:Spawn jail
A spawn jail is a player-created structure that can be built on multiplayer servers that traps newly spawned players. It can be used as a security check for new arrivals, or as a server lock for when there are no operators online.
Spawn jails have been mostly made obsolete in current versions of Minecraft by more purpose-built features: a whitelist can be used to limit access to the server, or setting the default game mode to adventure mode can allow players to join but not break or place anything until they are switched to survival or creative mode by a moderator. Additionally, since players' locations are saved when they log out and beds can be used to change the spawn point, spawn jails can only effectively be used to gate newly joining players. Despite all of this, they can still be built and may occasionally be useful as a tool for server moderation.
Description
[edit | edit source]A spawn jail is, in general, any structure that makes the player unable to move from the spawn point, or one that traps the player. A spawn jail can be built in several ways, but the most common examples include:
- 6
Bedrock blocks being placed in the sides, on the top and on the bottom. 
Barrier blocks.
Obsidian boxes filled with water and the 
Water Breathing effect.
- Not technically unbreakable; destroying a single block takes around 20 minutes, but it could potentially be automated by a malicious player using client mods. Prefer one of the above blocks.
The majority of spawn jails include blocks that normally cannot be broken by the player, such as listed above.
The world spawn in multiplayer servers spans a 21×21[Java Edition only]/11×11[Bedrock Edition only] area by default. This can be changed with the respawn_radius[Java Edition only]/spawnradius[Bedrock Edition only] gamerule. Alternatively, players in adventure mode will always spawn directly on the world spawn point.
Function
[edit | edit source]New arrivals spawn inside the box and cannot escape until released by an operator. If there are no operators or administrators online, the spawn jail effectively closes the server to new players, meaning no one can enter when the server is not managed. This is an anti-griefing measure: each new arrival feels scrutinized, may be followed once allowed out, and knows that the server is policed, purportedly making them less likely to grief.
Other variants
[edit | edit source]Sometimes, a spawn jail is more of a "spawn maze" where a maze built of bedrock starts at the spawn point and acts as an intelligence test for new arrivals; they must find the end of the maze in order to access the room properly. Maze generators can be found on the internet.
Some servers may have an entire section fenced off by bedrock. This is so the admins can let players on the server when no admins are online. It may also provide more selective server entrance policies, only letting those with good building talent or a premium membership in.
