Core Keeper Server Hosting

What is a Core Keeper dedicated server, and who is it for?

The Core Keeper dedicated server is the official application that runs the game's co-op world independently of the players. It is published on Steam as a separate tool and can be downloaded through SteamCMD with an anonymous login. When you host from your own PC the world only lives while you play; on a separate server crops keep growing, friends can head into the mines while you are away and all progress stays in one place.

• A group of friends who play at different times wants to progress in a shared world.
• The host's PC or internet connection struggles to carry the session.
• You want cross-play with players from Epic, Microsoft Store or GOG.

Core Keeper is light on CPU and memory, so big hardware is not needed. Still, keeping a server online for weeks, a save file that grows with the world and the need for a stable network make a dedicated server more sensible than a home PC.

What is the difference between Game ID and Direct Connect?

A Core Keeper server runs in one of two connection modes, and your choice determines both port settings and cross-platform support.

Game ID mode simplifies setup and hides the IP address, but because traffic goes through the relay network, latency depends on where the relay point is. With Direct Connect players connect straight to the server, so the advantage of a data center in Türkiye is felt in full; in exchange you must open the port and pay more attention to DDoS protection. According to community documentation, -port, -password and -ip are read only from the command line, not from the config file.

A practical tip: if you are a small Steam-only group, start with Game ID, the shortest path with no router settings. If someone plays via the Xbox app or Epic, or you want the lowest latency, switch to Direct Connect. Switching only changes a launch parameter and the world file is the same in both modes, so trying it is risk-free.

How many resources does a Core Keeper server need?

A small group usually plays comfortably with 2–3 GB of RAM and two cores; the values in the table are estimates and depend more on the size of the explored area than on player count. The game keeps explored regions and placed objects in memory, so long automation lines, many creature farms and big bases increase both memory use and save time.

• CPU: the simulation is not heavy, but intense combat and automation cause short spikes. Dedicated cores smooth them out.
• Memory: on Linux the server runs on a virtual display via Xvfb, which adds a little memory use.
• Disk: world files are stored compressed, but leave room for several world slots and backups.

The player cap is set with maxNumberPlayers or -maxplayers; according to community documentation the default is 8 if nothing is given on the command line. For a busier world use the top row of the table and watch usage for a few weeks.

The easiest way to monitor memory is to check free -h and htop after the server has been up for a few hours. If usage sits near the limit, consider upgrading; swap space can stop the server crashing on sudden memory spikes, but a game server that swaps often starts to stutter. The lasting fix is enough physical memory.

Should you choose a ready-made package or a VDS for Core Keeper?

This page shows VDS packages for Core Keeper: you can install the server yourself or request a ready-made setup through a support ticket. Because the VDS cores and memory are reserved for you, performance stays predictable even if you run another game or a Discord bot on the same machine.

On a VDS you control everything: update with SteamCMD whenever you like, switch between world slots (-world, 0–29) and define the server as a systemd service that restarts itself after a crash. Core Keeper is happy on a small machine, so hosting a second game on the same VDS is also possible.

For a detailed comparison see game server package or VDS. If you are not used to the Linux command line, a Windows Server install feels close to the game client; Linux uses fewer resources. Pick the right size from the live package table.

How do you configure the world with ServerConfig.json?

The Core Keeper server creates ServerConfig.json on first launch; most world settings are managed there or through equivalent launch parameters. On Windows the file is in the Pugstorm\Core Keeper\DedicatedServer folder of the user profile; on Linux it sits in the Unity config directory. Stop the server before editing.

Creative and normal worlds cannot be converted into each other; to change mode, create a new world in another slot. Pinning the Game ID saves players from hunting for a new ID after a reinstall. Choose a long, random value that is hard to guess: anyone who knows the Game ID can find your server, so share it only with your community.

Can you install mods on a Core Keeper server?

Official Core Keeper mod support runs on mod.io, and some mods must also be installed server-side. Each mod's description says whether it is client-only or needs both client and server; adding mods without reading this is the most common cause of connection errors.

1. Check each mod's server compatibility and the game version it needs.
2. Stop the server and back up the world.
3. Upload the mods to the folder the mod author specifies, using SFTP.
4. Make sure players install the same mods at the same versions.
5. Start the server and check the log for mod loading errors.

After a game update mods can stay incompatible for a while; postponing the server update or temporarily disabling mods reduces the risk of world corruption. A backup taken before a major update is the only safe way back.

Groups that prefer vanilla still have plenty of server-side options: world mode, seed, player cap and seasonal events. Keep a copy of your vanilla world in a separate slot before trying mods, and keep the mod list and versions in a text file to make installation instructions easier.

How do you keep a Core Keeper server secure?

In Game ID mode your server's IP address is hidden from players, so the risk of direct attacks is low; with Direct Connect the IP is exposed and network-level protection matters. On LIONFIN infrastructure DDoS traffic is filtered at network level by the RouteFence firewall, and 600 Gbit/s of total upstream capacity helps absorb sudden traffic surges (more on our data center).

• Password: in Direct Connect set a join password with -password and share it only within your community.
• Platform limit: to accept Steam players only, use the -allowonlyplatform parameter mentioned in community documentation.
• Ports: keep only the game port you use open and close the rest with a firewall.
• System security: run the server as a separate user, connect to SSH with a key and install OS updates regularly.

How do you move a Core Keeper world to the server and back it up?

A world you started on your own PC can be moved to the server: world files live in the worlds folder and are named by slot number, such as 0.world.gzip. On Windows the saves are under the Pugstorm\Core Keeper folder of your user profile, in a subfolder named after your Steam ID.

1. Stop the server and back up the existing world on it.
2. Upload your local world file to the server's DedicatedServer/worlds folder.
3. Make sure the file name and the world value point to the same slot.
4. Start the server, connect and check your base.

For backups, compress the world folder regularly and copy it off the server; the files are small, so daily or even hourly backups cost little disk space. Always take a manual backup before major game updates and mod changes.

How do you run a Core Keeper server as a service on Linux?

The most robust way to keep Core Keeper running on Linux is to define it as a systemd service, so it starts automatically after a reboot and restarts after a crash. The server starts with the _launch.sh script in the SteamCMD install folder, which brings up Xvfb for the virtual display itself.

Recommended layout: create a separate user such as corekeeper, install the files in its home directory and run the server as that user with the User= line in the service file. ExecStart points to the launch script and Restart=on-failure restarts it after a crash. Follow the logs with journalctl -u corekeeper.

This is far more reliable than leaving a terminal open or depending on a screen session, and the server doesn't stop when your SSH connection drops. On Windows Server you can do the same with Task Scheduler or a service wrapper; the logic is identical: the server must start without anyone logging in and recover by itself.

How do you improve latency and connection quality on a Core Keeper server?

Lag in Core Keeper has two sources: the network path to the server and the load on the server itself. In Game ID mode traffic goes through Steam's relay network, so the latency players see depends more on the relay point than on the server's location. In Direct Connect mode players connect straight to the server; if the server is in Türkiye and so are the players, the path is shorter.

• If most players are in the same region, try Direct Connect and compare both modes with your group.
• Players on Wi-Fi often get stutters from packet loss on their home network; a wired connection shows the difference immediately.
• Areas with heavy automation or many creatures stress the CPU; if stutter happens in one area, the cause is the simulation, not the network.
• If other heavy jobs run on the same machine, a server with dedicated resources reduces fluctuations.

Telling latency apart from server load is the first step: if everyone stutters at once, look at the server; if only one player does, look at that player's connection.

How do you update a Core Keeper server and manage seasonal events?

The server is updated with SteamCMD: stop it, back up the world and run app_update 1963720 validate again. Players' clients update automatically through Steam, so a server left behind is the most common cause of connection errors. The first launch after an update may take a while to convert the world; don't interrupt it.

The game runs seasonal events at certain times of the year. According to community documentation the server follows the real calendar by default; you can force a specific event with the seasonOverride setting or the -season parameter. This lets a group that missed an event play it later, but event items can leave lasting traces in the world.

A regular maintenance rhythm helps on long-running worlds: check for updates weekly, back up before every update and prune old backups monthly. On a VDS you can automate these steps with a simple script and a cron job, so players only notice a few minutes of downtime.

What are the most common Core Keeper server problems?

Core Keeper server issues usually come from Linux dependencies, connection-mode confusion or version mismatches.

• The server won't start on Linux: Xvfb or required libraries are missing. Community guides recommend the xvfb and libxi6 packages plus the Steamworks SDK Redistributable (app ID 1007).
• GameID.txt isn't created: the server hasn't finished its first launch; check the log and confirm the server can reach Steam.
• Friends can't connect by IP: the server is in Game ID mode. Enable Direct Connect with -port and open the matching UDP port.
• An Epic or GOG player can't join: cross-play only works in Direct Connect mode.
• “Version mismatch” warning: the game updated but the server didn't. Run app_update 1963720 again in SteamCMD.
• A setting change doesn't apply: the file was edited while the server was running, or the value is read only from the command line.

If you get stuck, open a support ticket from the customer panel with the log file attached.