Overview
Learn how to use Polymerium — from your first instance to advanced modpack development.
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Polymerium is a cross-platform, open-source Minecraft launcher built around a declarative instance profile:
Your instance is defined by a profile, not by a pile of file copies.
Polymerium stores downloaded package files in a shared cache and deploys each instance from its profile, Pack Source, and Local Data. This keeps managed files reusable while leaving you in control of data created by the game.
Where to Start
- New to Polymerium? Follow the Getting Started guide — you'll be playing in minutes.
- Coming from another launcher? Check the Migration Guide for a quick transition.
- Curious how it works? Read Core Concepts to understand what makes Polymerium different.
What You'll Find Here
| Section | What It Covers |
|---|---|
| Getting Started | Download, install, create an instance, add mods, play. |
| Core Concepts | Profiles, packages, the three managed directories, and deployment. |
| Managing Instances | Accounts, modpack import/export, package groups and override order, collections, recipes, tags, snapshots, and Java. |
| Advanced | Deployment rules, workspace, modpack development, CLI, MCP/AI agent mode. |
| Guides | Step-by-step walkthroughs for specific tasks — no theory, just doing. |
| Appendix | On-disk compatibility transitions and known limitations. |