Setting up a Core Keeper server

Updated 4 Nov 2026

Join your server

The first start downloads Core Keeper from Steam, so it takes a few minutes. Watch the Console tab. When it stops scrolling, your server is ready.

Players join with a Game ID. The console shows it. In the game, choose Join Game and paste it.

Keep the same Game ID

The ID changes every restart. To keep it, set your own in Game ID on the Startup tab. At least 28 letters and numbers, without Y, y, x, 0 or O.

World settings

SettingWhat it does
World NameThe world name.
World Seed0 for random.
World Mode0 normal, 1 hard.
Max PlayersUp to 100.

Seed and mode only apply to new worlds.

Bring your own world

  1. On your PC, open %userprofile%\AppData\LocalLow\Pugstorm\Core Keeper\Steam, then your ID, then worlds.
  2. Upload the file to .config/unity3d/Pugstorm/Core Keeper/DedicatedServer/worlds with the server stopped.
  3. Name it to match the World Index, like 0.world.gzip.

Problems

The Game ID is wrong

It changes on restart unless you set your own.

My Game ID is refused

Use 28+ letters and numbers, without Y, y, x, 0 or O.

My world did not load

Check the file name matches the World Index.

Still stuck? Open a ticket and we will take a look.
Open a ticket

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