Technical

Survival runs Paper. That is already not a Mojang dedicated server. Most Paper knobs here are pushed back toward stock Java Edition (entities keep ticking, hoppers are not slowed when full, TNT is not capped). A few are not: mob caps, spawn attempt rate, per-player spawn accounting, redstone implementation, and Paper’s “unsupported” block-update patches being left off.

The sky overworld is a separate Fabric 26.2 server, not a second Paper world. How you get there is on Features. Yellow marks values that are not current vanilla Java, or software defaults that change vanilla. These are the live files.

The plugins list is survival Paper, the Velocity proxy, and the Fabric sky mods.

What you feel in game

bukkit.yml

Spawn limits and spawn attempt rates. Vanilla Java uses a creature cap of 10, ambient 15, water creature 5, and tries monster spawns every tick.

spawn-limits:
  axolotls: 8
  water-underground-creature: 4
  water-ambient: 10
  monsters: 70
  animals: 8
  water-animals: 10
  ambient: 8
ticks-per:
  monster-spawns: 4
  animal-spawns: 200
  water-spawns: 200
  autosave: 6000

spigot.yml

entity-activation-range at 0 means loaded entities in that category tick normally at any distance — stock Java, not Paper’s default freeze. max-tnt-per-tick: 0 is unlimited. tab-complete: 0 turns command tab-complete off.

commands:
  tab-complete: 0
world-settings:
  default:
    mob-spawn-range: 8
    nerf-spawner-mobs: false
    enable-zombie-pigmen-portal-spawns: true
    entity-activation-range:
      animals: 0
      monsters: 0
      raiders: 0
      misc: 0
      water: 0
      villagers: 0
      flying-monsters: 0
    hopper-amount: 1
    max-tnt-per-tick: 0

paper-world-defaults.yml

World-level Paper. Anti-xray is Paper engine-mode 1 (enclosed ores rewritten to stone/deepslate in the chunk packet; cave-exposed ores stay visible). Nether and mirror nether use a debris/quartz/gold list instead. The End leaves it off. Wither and wither-skull entities are capped at 5 saved per chunk. Phantoms only attack insomniacs, same as stock Java. Merge-items-horizontally and the AlternateCurrent redstone engine are Paper, not Mojang.

anticheat:
  anti-xray:
    enabled: true
    engine-mode: 1
chunks:
  entity-per-chunk-save-limit:
    item: 4096
    wither: 5
    wither_skull: 5
  prevent-moving-into-unloaded-chunks: true
collisions:
  allow-player-cramming-damage: true
  max-entity-collisions: 4096
entities:
  behavior:
    only-merge-items-horizontally: true
    phantoms-only-attack-insomniacs: true
  spawning:
    count-all-mobs-for-spawning: true
    per-player-mob-spawns: true
    spawn-limits:
      ambient: 8
      axolotls: 4
      creature: 8
      monster: 70
      water_creature: 4
    ticks-per-spawn:
      monster: 4
hopper:
  cooldown-when-full: false
misc:
  redstone-implementation: EIGENCRAFT
unsupported-settings:
  disable-world-ticking-when-empty: true
  fix-invulnerable-end-crystal-exploit: false

Ender pearls through unloaded chunks and invulnerable end crystals are left as Mojang left them. Paper would patch both; this world does not.

paper-global.yml

These “unsupported-settings” flags turn Paper’s extra patches off, so several old block-update behaviors that current Java no longer does can still happen here. That is a config fact, not a tutorial.

proxies:
  velocity:
    enabled: true
    online-mode: true
unsupported-settings:
  allow-headless-pistons: true
  allow-permanent-block-break-exploits: true
  allow-piston-duplication: true
  allow-unsafe-end-portal-teleportation: true
  skip-tripwire-hook-placement-validation: true

Fabric sky server

Sky is its own JVM: Fabric Loader 0.19.5 on Minecraft 26.2, same game version as Paper survival. The overworld, nether, and end here are the old Paper sky map. Seeds stay unpublished. How you enter (Dragon's Breath, fly above Y 1320) is on Features. /server fabric is blocked on the proxy.

This is not Paper, so none of the bukkit/spigot/paper knobs above apply. Mob caps, hopper cooldown, TNT caps, activation range, and AlternateCurrent redstone are stock Java. Lithium is loaded with an empty (default) config, so it is meant to be vanilla-equivalent performance work only.

What you feel in the sky

server.properties

Vanilla dedicated defaults in the left column of the table above. online-mode is false because Velocity already authenticated the session (FabricProxy-Lite). Direct connect is rejected.

difficulty=hard
gamemode=survival
spawn-protection=0
view-distance=16
simulation-distance=10
max-players=100
online-mode=false
pause-when-empty-seconds=-1
enforce-secure-profile=false
allow-flight=false
generate-structures=true
sync-chunk-writes=true
entity-broadcast-range-percentage=100

SkyWorlds gate

Same numbers on the Paper plugin and the Fabric mod. Playable space is at or below the threshold; the transfer mirrors you around the pivot so you do not bounce.

threshold_y: 1320
pivot_y: 1321
transition_ticks: 60
cooldown_ticks: 200
fade_ticks: 50

Plugins

Jars currently in the survival plugins folder, on the Velocity proxy, and in the Fabric sky mods folder. Lobby, PvP, and creative plugins are not listed. Names link to source: our GitHub when we wrote it, otherwise the author’s GitHub or project page.

Survival

Velocity proxy

Fabric sky