Worlds: Multiverse for Fabric

Evidence

Ran on Kiln's test stand (2026-11-04): McWorldMod did not start: java.lang.NoClassDefFoundError: net/minecraft/server/MinecraftServer; McWorldsClient did not start: java.lang.NoClassDefFoundError: net/minecraft/network/protocol/common/custom/CustomPacketPayload.

What it needs from Kiln

• Mixin
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking.Context
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking.PlayPayloadHandler
• net.fabricmc.fabric.api.command.v2.CommandRegistrationCallback
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerLevelEvents
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerLevelEvents.Load
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerLevelEvents.Unload
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents.EndDataPackReload
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents.ServerStopped
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerTickEvents
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerTickEvents.EndTick
• net.fabricmc.fabric.api.event.registry.FabricRegistryBuilder
• net.fabricmc.fabric.api.networking.v1.PayloadTypeRegistry
• net.fabricmc.fabric.api.networking.v1.ServerPlayNetworking
• net.minecraft.SharedConstants
• net.minecraft.WorldVersion
• net.minecraft.client.gui.screens.options.InWorldGameRulesScreen
• net.minecraft.commands.CommandBuildContext
• net.minecraft.commands.CommandSourceStack
• net.minecraft.commands.Commands
• net.minecraft.commands.Commands.CommandSelection
• net.minecraft.commands.SharedSuggestionProvider
• net.minecraft.commands.arguments.EntityArgument
• net.minecraft.commands.arguments.IdentifierArgument
• net.minecraft.commands.arguments.ResourceKeyArgument
• net.minecraft.commands.arguments.coordinates.Vec3Argument
• net.minecraft.core.Direction.Axis
• net.minecraft.core.RegistryAccess
• net.minecraft.core.RegistryAccess.Frozen
• net.minecraft.data.worldgen.features.MiscOverworldFeatures
• net.minecraft.nbt.CompoundTag
• net.minecraft.nbt.IntTag
• net.minecraft.nbt.ListTag
• net.minecraft.nbt.NbtAccounter
• net.minecraft.nbt.NbtFormatException
• net.minecraft.nbt.NbtIo
• net.minecraft.nbt.NbtOps
• net.minecraft.nbt.NbtUtils
• net.minecraft.nbt.Tag
• and 80 more

On the roadmap: Minecraft's libraries and client API (0.2), Code next to data (0.3), Mixin (0.5)

In the author's words

Run unlimited worlds on one Fabric server, like Multiverse on Paper, World Manager or Multiworld: create, list and teleport with commands. Every world keeps its own time, weather and game rules, and the End dragon, portals and maps work in all of them.

Scan

Scanned on 4 November 2026 against Kiln 0.2.0, file worlds-1.11.0+26.3.jar. The scan reads the mod's classes; it does not run them.