What Slimefun works with.
| Platform | Java Edition |
|---|---|
| Loaders | Bukkit, Spigot, Paper |
| Minecraft versions | 1.8.8, 1.16.5, 1.18.2, 1.20.1, 1.21.1, 1.21.8, 26.1.2, 26.2 |
Slimefun turns a Paper or Spigot server into a modpack-like experience without any client-side mods, adding over 500 items across two progression trees: Technology (power grids, multiblock machines, nuclear reactors) and Magic (altars, wands, soulbound gear). Hangar lists the plugin as compatible from Paper 1.8 through the current 26.2 release, all from a single jar. The original Slimefun4 repository stopped shipping real updates in 2025, so this page covers Slimefun5, the community fork that carries active development forward.
What happened to the original Slimefun4
Slimefun started in 2013 and grew into one of the most-used Paper plugins, with over 1,100 stars on its original repository. Development there went quiet in spring 2025: the last commit that changed real plugin code landed in March, only a routine CI-config commit followed in May, and the last GitHub release, RC-37, shipped back in February 2024. The project's own README still describes Minecraft 1.16 through 1.20 as current.
TheBusyBiscuit, Slimefun's long-time lead developer, and several other original maintainers now put their commits into Slimefun5 instead, a separately hosted fork that keeps the plugin's original package name and item set. Hangar's own listing for the plugin describes Slimefun5 as a community-maintained continuation of Slimefun4 after the original was discontinued by its developers, and it is the version this page tracks.
Installing Slimefun on Paper
- 1.Download the current build from the Slimefun project page on Hangar, or from the Slimefun5 GitHub releases.
- 2.Drop the jar into the server's plugins folder and start the server once to generate its config.
- 3.Run /sf guide in-game to open the Slimefun guide book and browse the unlocked categories.
- 4.Click a LOCKED item in the guide to research it; research spends experience levels rather than items.
- 5.Check plugins/Slimefun/config.yml for the auto-updater and metrics options before your next restart.
Supported Minecraft versions and requirements
Slimefun ships as a single Java 8-bytecode jar built to run on legacy and current servers alike. Hangar's release history lists Paper compatibility from 1.8 through the current 26.2, and the plugin declares an API version floor of 1.13 specifically so the same jar loads across that whole range. Building Slimefun from source needs a newer Java 25 toolchain for its automated test suite, but that requirement is for contributors, not for anyone just running the plugin.
- Paper or Spigot, or a Bukkit-based fork of either
- Minecraft 1.8 through the current 26.2 release, per Hangar's supported-versions list
- Java 8 or newer on the server running the plugin
Integrations and permissions
Slimefun's plugin manifest lists PlaceholderAPI, WorldEdit, ClearLag, mcMMO, ItemsAdder, and Orebfuscator as soft dependencies it hooks into automatically when they are present, and none of them are required to run the plugin. Slimefun ships no bundled permissions plugin. Its own permission nodes, prefixed slimefun., default to either everyone or server operators out of the box, so a permissions plugin such as LuckPerms is what most servers use to hand out finer-grained access.
- PlaceholderAPI: placeholders for research progress and player stats
- WorldEdit, or FastAsyncWorldEdit as a drop-in replacement, for a few machine interactions
- mcMMO: cross-plugin experience and ability hooks
- ItemsAdder: custom item and texture compatibility
- ClearLag and Orebfuscator: lag-management and anti-xray integrations
Slimefun beginner walkthrough
Questions about Slimefun.
5 questions
Is Slimefun still maintained?
Yes, but not under the original repository. Slimefun4's own GitHub project went quiet in 2025, with almost no commits after March and no release since February 2024. Active development continues under Slimefun5, a fork that several original maintainers, including long-time lead developer TheBusyBiscuit, contribute to. This page tracks Slimefun5 as the currently maintained version.
What happened to Slimefun4?
The original Slimefun4 repository stalled in 2025. Commits slowed to almost nothing after March, the last stable release, RC-37, dates to February 2024, and the project's own README still lists Minecraft 1.16 through 1.20 as current. Its developers moved their work to a new repository rather than formally announcing a shutdown, which is why the old project looks abandoned rather than closed.
What is Slimefun5?
Slimefun5 is a community-maintained continuation of Slimefun4, run by a separate GitHub organization of the same name. It keeps the same GPL-3.0 license and the same core item set, and Hangar lists it as the project named simply Slimefun. Active development, including support for the current 26.x Minecraft releases, happens there rather than on the original repository.
Which Minecraft versions does Slimefun support?
Hangar lists Paper compatibility from Minecraft 1.8 through the current 26.2 release, all from one jar built with a Java 8 bytecode floor so it loads on old and new servers alike. Building from source needs a newer Java 25 toolchain for testing, but that only matters to contributors, not to server owners installing the plugin.
Does Slimefun need a permissions plugin?
No. Slimefun ships its own permission nodes, prefixed slimefun., that default to either everyone or server operators out of the box. Most servers still install a permissions plugin such as LuckPerms to hand specific nodes, like item or research cheats, to individual staff ranks instead of relying on the blanket operator default.
