spawn-limits

Spawn limits can be configured in the [bukkit](/bukkit).yml file. By default, it looks like this:

spawn-limits:
  monsters: 70
  animals: 10
  water-animals: 5
  water-ambient: 20
  water-underground-creature: 5
  axolotls: 5
  ambient: 15

Recommended starting values

If you run a small server with just a few friends, these values should work fine and still give a fairly vanilla experience (these are similar to the default bukkit values):

spawn-limits:
  monsters: 60
  animals: 12
  water-animals: 5
  water-ambient: 12
  water-underground-creature: 4
  axolotls: 4
  ambient: 4

For medium-sized servers (10-30 players), you can try these values:

spawn-limits:
  monsters: 35
  animals: 7
  water-animals: 3
  water-ambient: 5
  water-underground-creature: 2
  axolotls: 2
  ambient: 2

And for larger servers, try these values:

spawn-limits:
  monsters: 20
  animals: 4
  water-animals: 2
  water-ambient: 2
  water-underground-creature: 1
  axolotls: 1
  ambient: 1

Mob spawn range

Because lowering the spawn rate causes fewer mobs to spawn, you may want to make the mobs that do spawn closer to the players.

Please see the mob-spawn-range page for help on doing this. As a general rule: if you lower the spawn limits, you should lower the mob spawn range as well.

A note on per-player-mob-spawns

This page relies on the per-player-mob-spawns option being set to true in your paper-world-defaults.yml file. This is highly recommended, and the guide does not support this option being set to false.

Please see this page for more info on what this option does and why you should enable it.

What are spawn limits?

Spawn limits are probably the most important configuration option for optimisation, perhaps with the exception of [ /[[minecraft](/ /[[minecraft)/properties/simulation distance|simulation-distance]].

Spawn limits are sometimes also referred to as “mob caps”. For the sake of this guide, they’re effectively the same thing.

It effectively controls how many mobs (animals, monsters, etc) can be present in the world at any given time.

With per-player-mob-spawns enabled, this limit is calculated per player in the world, meaning that each player gets their own “quota” of mobs.

When the number of mobs around a player goes above this limit, no new mobs will be able to spawn until the number of mobs drops back below the limit.

Basically, a monster mob cap of 70 means that up to 70 monster mobs can be present around each player at any given time, for example.

The different mob types

Thanks to https://paper-chan.moe/paper-optimization/#mob-categories, we have a detailed list of what mobs fall into each category.

Feel free to search for specific mobs using your browser’s search function (ctrl+f) if you’re not sure which category they fall into!

Monsters

Animals / creatures

Ambient

Yep, that’s it… you can probably lower this one quite a bit, if not completely to 0. I’ve seen some servers’ spark reports showing thousands of bats where optimisation has gone horribly wrong…

Water animals / water creature

Water ambient

Water underground creature

Axolotl

Pretty obviously… axolotls. They’re so cute they get their own category.

Misc

Everthing else: