GeckoLib | 3D Animation Library Mod

What Is GeckoLib?

GeckoLib is a 3D animation and rendering engine for Minecraft Java Edition mods. It's a developer library, not a standalone mod you interact with in-game. Other mods install it as a dependency so their custom entities, blocks, items, and armor can move. If you've ever seen a Minecraft mob with silky, Bedrock-style keyframe animations, there's a good chance GeckoLib was doing the rendering behind the scenes. Mods you may already know that lean on it include From the Shadows and Mowzie's Mobs, both of which use it for their animated creatures.

Built by bernie-g and a team of contributors, the project is open source under the MIT license. It has racked up tens of millions of downloads, making it one of the most widely adopted animation libraries in the modding scene.

What GeckoLib Adds

GeckoLib's feature set is aimed at modders who want console-quality animation without writing a custom engine:

• Complex 3D keyframe-based animations for entities, blocks, items, armor, and more
• 30+ easing types plus catmull-rom smoothing for fluid transitions
• Concurrent animation support so a single entity can run several animations at once
• Sound and particle keyframes that trigger audio or effects at specific frames
• Event and instruction keyframes for firing custom logic at exact moments
• Molang math animations using queries like query.limb_swing for procedural motion
• Per-bone render layers and animated textures with glowmasks for detailed models
• Memory compression for animation data, which keeps large modpacks lighter

Players benefit indirectly: when a mod you love lists GeckoLib as a required dependency, installing it is what makes that mod's creatures actually move.

How to Install GeckoLib

Because GeckoLib is a library, you usually install it because another mod requires it. The host mod's page will say so. The install itself is the same as any Minecraft mod:

1. Make sure your loader (Fabric, Forge, NeoForge, or Quilt) is installed and matches the Minecraft version of the mod that needs GeckoLib.
2. Download the matching GeckoLib JAR for that exact loader and version combination.
3. Drop the JAR into your .minecraft/mods folder.
4. Do the same for the mod that depends on it, then launch the game.

If you're new to loaders in general, our how to install Minecraft mods walkthrough covers the full setup.

Compatibility and Known Issues

GeckoLib covers a remarkably wide range of Minecraft versions, and each one has its own GeckoLib build. Always match the JAR to your game version and loader. Mixing a Forge GeckoLib build with a Fabric install (or vice versa) won't load.

For modders, the project's documentation covers setup, entity, and renderer guides, including the GeckoLib 5 installation path and the Blockbench export workflow. If a mod that depends on GeckoLib ever crashes on startup, the first thing to check is whether your GeckoLib version matches what that mod was built against.

FAQ

Do I need GeckoLib if I'm not a modder? Only if a mod you've installed lists it as a required dependency. On its own it adds nothing visible to your game.

Is GeckoLib client-side or server-side? It's designed to run on the client for rendering. Many mods that use it ship it as a client-and-server dependency, so follow the host mod's instructions.

Is GeckoLib free and open source? Yes. It's MIT licensed, developed by bernie-g and contributors, with source on GitHub and a community Discord.