Optimize the Paper configuration of your Minecraft server

Open them in the Files tab. Purpur reads all of these too, plus its own purpur.yml. For the differences between the server types, see Paper, Purpur or Spigot.

1. Make a backup in the Backups tab, so a broken file is one restore away.
2. Change one group of settings.
3. Save the file and restart the server. Paper reads these files at start.
4. Check the console for config errors, then compare TPS with the evening before.

YAML files use spaces for indents, never tabs. A wrong indent can stop the file from loading, and the console names the line.

Mobs further from a player than the activation range tick less often: they stand still until something wakes them. This is one of the biggest savings on a server with many animals and villagers.

world-settings:
  default:
    entity-activation-range:
      animals: 24
      monsters: 24
      raiders: 48
      misc: 8
      water: 8
      villagers: 24
      flying-monsters: 32

Changes gameplay: farms that need mobs to move, such as some mob grinders, work slower when the player stands far away. Very low ranges make mobs stand still close enough for players to see it.

bukkit.yml sets how many mobs of each kind may exist in the area around players. Fewer mobs means fewer entities to tick.

spawn-limits:
  monsters: 50
ticks-per:
  monster-spawns: 2

• spawn-limits.monsters is 70 by default. 50 is still a dangerous night, with fewer mobs to tick.
• ticks-per.monster-spawns is 1, so the server tries to spawn monsters every tick. 2 halves those attempts.
• ticks-per.animal-spawns is 400 by default and can stay.

config/paper-world-defaults.yml has the same limits under entities.spawning.spawn-limits and ticks-per-spawn. Their default is -1, which means: use the value from bukkit.yml. Set a number there only to give one world other limits.

Leave entities.spawning.per-player-mob-spawns at true. It spreads spawns over players, so one player's mob farm does not use up the spawns for everyone else.

collisions:
  max-entity-collisions: 2
chunks:
  entity-per-chunk-save-limit:
    arrow: 16
    ender_pearl: 8
    experience_orb: 16
    fireball: 8
    small_fireball: 8
    snowball: 8

The save limit only applies when a chunk is saved and unloaded. It does not remove anything in loaded chunks, so players do not see items vanish in front of them.

Mobs further than the hard despawn range from every player are removed at once. Between the soft and the hard range they despawn at random. In Paper each mob category has its own pair:

entities:
  spawning:
    despawn-ranges:
      monster:
        soft: default
        hard: 96

default uses the normal game values, 32 soft and 128 hard for monsters. A hard range of 96 removes far monsters sooner, so new ones can spawn near players.

Item despawn in spigot.yml and Paper

• item-despawn-rate in spigot.yml is 6000 ticks, which is five minutes, the same as the normal game. Lowering it to 4000 clears dropped items after about three and a half minutes. This changes gameplay: players who die have less time to fetch their items.
• entities.spawning.alt-item-despawn-rate in paper-world-defaults.yml sets a shorter time for listed items only. Turn it on with enabled: true and list items such as cobblestone: 300, so cheap blocks from mining vanish after 15 seconds while tools and armour keep the full five minutes.

Dropped items of the same type that lie close together merge into one stack. Fewer stacks means fewer entities. The radius is set per world in spigot.yml, in blocks:

world-settings:
  default:
    merge-radius:
      item: 2.5
      exp: 3.0

Check the current values in your file first. A larger radius merges more, which helps near mob farms and big explosions. It also makes items jump towards each other, which some item sorters do not expect. For exp, -1 keeps the normal game behaviour. On Paper, entities.behavior.only-merge-items-horizontally: true in paper-world-defaults.yml stops items from merging through floors.

ALTERNATE_CURRENT gives the same results as the normal game for almost all builds, but can change the order in which some contraptions fire. Test your players' main farms after switching. EIGENCRAFT is the third option.

Raising hopper-check makes empty hoppers react a few ticks later, which players rarely notice. Leave hopper-transfer at 8, because a different value changes the speed of every item sorter. Set hopper.disable-move-event to true only when no plugin uses hopper events; protection and shop plugins often do.

• environment.optimize-explosions in paper-world-defaults.yml is false. true caches parts of the blast calculation and makes TNT and creepers much cheaper. Blast results stay practically the same.
• max-tnt-per-tick in spigot.yml is 100. Lower it to 50 if players build TNT cannons that drop the TPS; extra TNT waits for the next tick.

On a fresh world with many explorers, set player-max-chunk-generate-rate to a number such as 40 to stop one player on an elytra from taking all the generation time. On a world that is already pre-generated, the limit hardly matters. Setting prevent-moving-into-unloaded-chunks to true holds fast players at the edge of loaded land until it catches up.

To give one world other values, create paper-world.yml in that world's folder, such as world_nether, and put only the keys you want to change in it. Every other key comes from paper-world-defaults.yml.

entities:
  spawning:
    spawn-limits:
      monster: 40

For spigot.yml, add a section with the world's folder name under world-settings, next to default. Restart after either change. When TPS is still low after these settings, reduce lag shows how to find the build or plugin behind it.