Deploy & Play

Deploy your instance and launch Minecraft — understand what "deploy" means and how launching works.

Last updated on

Deploying Your Instance

Before Minecraft can run, Polymerium needs to deploy your instance. This is the step where your metadata (version, loader, mod list) gets turned into an actual, runnable game directory.

Click Deploy — or just click Launch and Polymerium will deploy automatically if needed.

What Deploy Does

Downloads all required files — Minecraft jars, loader libraries, and mods — to the shared cache
Builds the game directory using symbolic links pointing into the cache
Generates launch parameters (classpath, JVM args, etc.)

First Deploy vs. Incremental Deploys

The first deploy downloads files that are not already in the shared cache. Its duration depends on the files needed and your connection.

Later deploys reuse valid cached resources and apply only the file operations needed to bring the Run Directory up to date.

Launching runs the deployment check even if you haven't changed the profile. Missing or damaged managed files can be repaired; files already in the expected state need no further work.

Launching

Click Launch to start Minecraft. The instance page offers Managed and Fire-and-forget modes; Debug mode is available after enabling the application's advanced controls:

Mode	What It Does
Managed (default)	Polymerium tracks the game process, captures output, and detects crashes. Recommended.
Fire-and-forget	Launches the game and detaches. Use this if you want to close Polymerium while playing.
Debug (advanced controls)	Exports the launch command for troubleshooting without starting the game.

First Launch Checklist

What's Next?

You're playing! Here's where to go from here:

Understand what just happened — read Core Concepts to learn why Polymerium works this way
Manage your instances — accounts, snapshots, tags
Go deeper — deployment rules, CLI, modpack development