server.properties explained, checker and generator

A link for reporting server bugs. The game offers it in the server links menu. Empty = no link.

World difficulty. On Peaceful no hostile mobs spawn and players don't get hungry.

Shows players the server rules on join, which they have to accept. The texts live in the codeofconduct folder (one file per language, e.g. en_us.txt).

Puts players into the gamemode mode every time they join.

Game mode for new players. Players who have joined before keep theirs (unless force-gamemode is on).

Hardcore: difficulty is locked to hard and a player who dies can only spectate.

The server description in the in-game server list. Colours and styles via § codes, a second line via \n.

When nobody is online for this many seconds, the world pauses to save CPU. 0 or less = never pause.

Accepts players sent here by another server (the /transfer command). Off = such connections are refused.

Allows flying in survival (mods, plugins). When off, the server kicks players who stay in the air for a few seconds.

Output of console commands is shown to operators in chat.

Output of RCON commands is shown to operators in chat.

Chat spam protection. The higher the number, the more quick messages a player may send before the server kicks them.

The same for commands: how many quick commands a player may send before the server kicks them.

Requires signed chat messages (a key from the Microsoft account). Players without a key can't join.

When the whitelist is turned on or reloaded, kicks online players who aren't on it.

The permission level datapack functions run with (1–4).

The server list shows only the number of players, not their names.

Write player IP addresses to the log when they join.

How many players can be online at once.

Checks players against Microsoft accounts. Off = anyone can join with any name. Only turn it off behind a proxy (Velocity, BungeeCord) that checks accounts itself.

The permission level /op gives (1–4). Level 4 can do everything, including /stop.

After how many idle minutes a player is kicked. 0 = never.

Rejects players connecting from a different network than the one they signed in to Microsoft from (VPN, proxy).

Radius around spawn, in blocks, where only operators can build. 0 = no protection. Has no effect while the server has no operators.

Only players on the whitelist can join (/whitelist add <nick>, file whitelist.json). On by default since 26.3.

How far players can see entities, as a percentage of the default (10–1000). Lower saves bandwidth and CPU.

Generate structures (villages, temples, strongholds…) in new chunks. Already generated terrain stays as it is.

Generator settings as JSON, mainly the layers of a flat world. Only used when the world is created.

Datapacks that stay disabled when a new world is created, comma separated.

Datapacks enabled when a new world is created, comma separated. Default vanilla; experimental features are enabled here too.

Name of the world folder. Changing it creates a new world (the old one stays on disk).

Seed for a new world. Empty = random. Only used when the world is created.

Type of a new world. Only used when the world is created.

How many chained block updates (redstone, water, sand…) may run at once. A brake against overloading the server. Negative = no limit.

The largest possible world radius (world border) in blocks.

Compression of world (region) files.

How far around a player (in chunks) the world ticks: mobs, farms, redstone, crops (2–32).

How many chunks around them players can see (2–32). Every extra chunk costs server memory and CPU.