Install a Core Keeper dedicated server via SteamCMD (Windows and Linux)

Want to self-host your Core Keeper server for cavern exploration with friends? This step-by-step guide walks you through installing the official dedicated server via SteamCMD. All commands, App ID and ports verified against the official Core Keeper wiki.

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Hardware requirements

Core Keeper typically uses 2-6 GB depending on map size and exploration. Plan 4 GB for 1-4 players, 6 GB for 5-8 players + large map.

Step 1 — Download SteamCMD

Windows

1. Download: https://steamcdn-a.akamaihd.net/client/installer/steamcmd.zip
2. Extract to C:\steamcmd\
3. Run steamcmd.exe once

Linux (Ubuntu/Debian)

sudo apt install lib32gcc-s1 wget unzip xvfb -y
mkdir ~/steamcmd && cd ~/steamcmd
wget https://steamcdn-a.akamaihd.net/client/installer/steamcmd_linux.tar.gz
tar -xvzf steamcmd_linux.tar.gz
./steamcmd.sh +quit

On Linux, xvfb (X virtual framebuffer) is required for Core Keeper’s headless builds (Unity dependency).

Step 2 — Install Core Keeper server (App ID 1963720)

The dedicated server App ID is 1963720 (not 1621690, the game client).

Windows

steamcmd.exe +force_install_dir C:\CoreKeeperServer\ +login anonymous +app_update 1963720 validate +quit

Linux

./steamcmd.sh +force_install_dir /home/corekeeper/CoreKeeperServer/ +login anonymous +app_update 1963720 validate +quit

Download size: ~1.5 GB.

Step 3 — Open network ports

Core Keeper uses 2 UDP ports: 27015 and 27016.

Windows — Admin PowerShell

New-NetFirewallRule -DisplayName "CoreKeeper" -Direction Inbound -Protocol UDP -LocalPort 27015,27016 -Action Allow

Linux — UFW

sudo ufw allow 27015/udp
sudo ufw allow 27016/udp
sudo ufw reload

Forward both UDP ports on your router.

Step 4 — First start

Windows

@echo off
cd /d "C:\CoreKeeperServer"
CoreKeeperServer.exe -batchmode -nographics -logfile server.log -world 0

Linux (with xvfb)

cd /home/corekeeper/CoreKeeperServer
xvfb-run -a ./CoreKeeperServer.x86_64 -batchmode -nographics -logfile server.log -world 0

Wait for this line in server.log:

Game ID: AbCdEfGhIjKlMnOp

This is your World ID (Game ID) — players need it to join.

Step 5 — Customize ServerConfig.json

Located in worlds/<index>/:

{
  "worldName": "My Core Keeper World",
  "worldMode": 0,
  "gameId": "",
  "discoveryMode": "Public",
  "maxConnections": 8,
  "serverIP": "0.0.0.0",
  "serverPort": 27015,
  "serverGameId": ""
}

Step 6 — Get the Game ID

grep "Game ID" server.log

Players enter this 16-char code in Core Keeper → Multiplayer → Join Other World.

Step 7 — Import an existing solo world

1. Locate your local save:
   • Windows: %USERPROFILE%\AppData\LocalLow\Pugstorm\Core Keeper\Saves\
   • Linux: ~/.config/unity3d/Pugstorm/Core Keeper/Saves/
2. Copy the world folder to <CoreKeeperServer>/worlds/<index>/
3. Restart the server

Step 8 — systemd service (Linux)

Create /etc/systemd/system/core-keeper.service:

[Unit]
Description=Core Keeper Dedicated Server
After=network.target

[Service]
Type=simple
User=corekeeper
WorkingDirectory=/home/corekeeper/CoreKeeperServer
ExecStart=/usr/bin/xvfb-run -a /home/corekeeper/CoreKeeperServer/CoreKeeperServer.x86_64 -batchmode -nographics -logfile /home/corekeeper/CoreKeeperServer/server.log -world 0
Restart=on-failure

[Install]
WantedBy=multi-user.target

sudo systemctl enable --now core-keeper

Step 9 — Update the server

steamcmd.exe +login anonymous +force_install_dir C:\CoreKeeperServer\ +app_update 1963720 validate +quit

Back up worlds/ before major updates.

FAQ

App ID 1621690 vs 1963720?

1621690 is the client. 1963720 is the dedicated server, free via anonymous SteamCMD.

How do my friends join?

Grab the Game ID from server.log (grep "Game ID"). Friends enter it in Core Keeper → Multiplayer → Join Other World. UDP 27015-27016 must be open.

Max players?

Officially up to 8 players cooperative.

Why xvfb on Linux?

Core Keeper is built with Unity and needs a graphics context even headless. xvfb-run provides a virtual X server without a real GPU.

Friends can’t join

Check: UDP ports 27015 and 27016 open (firewall + router), correct Game ID shared, discoveryMode = Public or FriendsOnly.

Conclusion

You now have a working Core Keeper dedicated server. Recommended next steps:

1. Get the Game ID from server.log and share it with friends
2. Customize ServerConfig.json with your world name
3. Enable automatic backups via cron or scheduled task

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Further reading

• Core Keeper hosting from €9.90/month
• Official Core Keeper wiki — Dedicated server
• SteamDB — Core Keeper Dedicated Server