Chunky

Chunky is a Minecraft Java mod and server utility that pre-generates world chunks before players explore them. Running a world generator in real-time as players move through new terrain is one of the most common sources of server lag and stuttering. Chunky solves this by letting you generate a defined area of the world in the background, so every chunk a player enters has already been built by the time they arrive.

The mod is maintained by pop4959 under GPL-3.0 and works across Fabric, Forge, and NeoForge on Java Edition from 1.13.2 through 1.21.5. It also ships as a standalone plugin for Bukkit, Paper, Folia, Spigot, and Sponge servers, making it one of the few performance tools that covers every major Java server environment.

How to use Chunky

Chunky runs entirely through commands. The typical workflow is to set a center coordinate and radius, then start generation:

• /chunky radius 3000 - sets the pre-gen radius in blocks (3000 covers a 6000 x 6000 block area).
• /chunky start - begins generating. Progress reports appear in chat at regular intervals.
• /chunky pause - pauses generation without losing progress.
• /chunky continue - resumes a paused task.
• /chunky cancel - cancels the current task entirely.
• /chunky status - shows progress, estimated time remaining, and chunks-per-second rate.

Generation runs in the background so the server or client stays playable during the process. For large worlds, running the pre-gen task overnight or before the server opens to players is the standard approach. You can also target a specific dimension with /chunky world before starting.

Installation

Download the correct jar for your loader from the Modrinth project page. Chunky provides separate jars for Fabric, Forge, NeoForge, and server software families. Drop the jar into your mods folder (Fabric, Forge, or NeoForge) or plugins folder (Bukkit, Paper, Spigot, Folia, Sponge), then restart.

• Fabric: requires Fabric Loader and Fabric API in the mods folder.
• Forge: drop into the mods folder, no extra libraries required.
• NeoForge: drop into the mods folder, no extra libraries required.
• Paper, Spigot, Bukkit, Folia: use the Bukkit-flavor jar in the plugins folder.

Client and server installation

Chunky is optional on both client and server, so you can install it on either side independently. The most common setup is server-only: players connect without needing to install anything themselves. You can also run it in a single-player world through the integrated server, which is useful before opening a world for the first time or before a large build session in ungenerated terrain.