Core Keeper Server Hosting

Why Run a Core Keeper Dedicated Server

In ordinary Core Keeper multiplayer, one player hosts the world and everyone else joins with a code. Pugstorm's own FAQ is clear that the host must be in the world for others to play, so the cavern closes whenever the host does. With players in different time zones or on different schedules, that means half the group is always waiting.

Dedicated servers fix that. Pugstorm released them on 11 May 2022, during Early Access, so that multiplayer worlds could be reached at any time without a host in the game, and the Core Keeper Dedicated Server has had regular improvements since. The Steam page sums up the result: 2 to 8 player drop-in, drop-out online co-op, with the option to host your own dedicated server.

You can run that server at home, but it means leaving a PC on and sharing your connection with the whole group. A rented server lives in a data centre with a fixed address, steady bandwidth and DDoS filtering, and you manage it from a web panel.

Core Keeper From Early Access to 1.3

Core Keeper has changed a lot since it entered Early Access, and some of those changes affect how a server should be set up.

Each major update has been followed by a run of stability patches. After 1.3 came 1.3.0.3 on 29 September, 1.3.0.5 on 7 October and the 1.3.0.6 hotfix on 9 October 2026, the newest at the time of writing.

How Players Join: Game ID or Direct Connection

A Core Keeper dedicated server offers two ways in, and since August 2025 they cover every PC storefront the game is sold on.

The server writes its Game ID to a GameID.txt file and its log to CoreKeeperServerLog.txt, both of which you can open in the File Manager. Since patch 1.1.2.3 a Game ID can be as short as 15 characters, and a server can be set to accept players from specific PC platforms only. Patch 1.1.2.4 added joining by IPv6 address. Admins can regenerate the Game ID from the pause menu if it has been shared too widely.

World Settings, Seeds and Seasons

Core Keeper 1.0 brought a new world generation system. When a world is created you can change settings such as the number of caverns, ore density and biome chaos, which controls how much the biomes overlap, and every world has a seed that can be shared. A dedicated server can create such a world too: since patch 1.0.0.6 it accepts ordinary text as a world seed, and its README explains how to set custom world generation parameters.

• World mode: set with a readable value such as -worldmode Hard, or the matching number.
• Season: seasonal events can be forced with values such as -season Easter.
• Seed: a text seed, or -hashedworldseed to set the hashed seed directly.
• Content: -activateallcontent activates every available content bundle automatically.
• Reference: ARGUMENTS.txt in the server files lists every command line argument.

On our servers these settings live in the panel's configuration. Stop the server, change them, save and start it again, and remember that the generation settings only apply when a new world is created.

Classic Worlds or a Fresh 1.0 World

At 1.0 every Early Access world became a Classic world. You can still load one and keep playing the Early Access sandbox, but Pugstorm calls these worlds unsupported, and 1.0 worlds are where development happens. The Passage, the endgame biome that surrounds the underground, and the new story content only appear in worlds created on 1.0 or later, and 1.0 worlds are finite, so travel far enough and you reach it.

• Keep a Classic world: fine for a group that just wants to keep building where it started.
• Start fresh: Pugstorm's recommendation for the full story and the full 1.0 experience.
• Do both: back up the Classic world, start a new one, and keep the old save for visits.

Slots, RAM and a Party of Eight

Core Keeper is built for 1 to 8 players, and its bosses scale with the size of the party. Pugstorm's 0.5.0 patch, for example, lowered boss health scaling slightly for 2 players and much more for 8. Our plans follow the game: 4 slots for a duo or a trio, 6 for a medium group and 8 for the full party.

The dedicated server is light by survival game standards, and patch 0.7.5 cut its CPU load by a third. Memory use grows with the size of the explored world and the amount of automation running at once, so the 4 and 6 slot plans include the free 5GB tier and the 8 slot plan includes 8GB. If the memory graph sits near the limit on a busy evening, step up a tier from the client area; your world stays where it is.

Running Mods on a Core Keeper Server

Core Keeper's mods come from mod.io and, since 1.2, from an opt-in Steam Workshop beta that Pugstorm plans to open fully once the tools are ready. On a dedicated server, mods are files: upload them with the File Manager or SFTP, and make sure every player runs the same mods in the same versions.

1. Back up the server before you add or update a mod.
2. Upload the mod files to the server and restart it.
3. Check the log for errors before you invite the group.
4. Keep the same load order on every PC; update 1.3 added a mods menu that shows it, and patch 1.3.0.5 fixed modded objects mixing up when the order changed.

Pugstorm is open about the risk: almost every update changes core game files, mods often stop working until their creators update them, and the team cannot update mods itself. Before a major update, check your mods' pages, take a backup and update the mods together with the server.

Admins, Backups and Updates

Admin rights are handed out in game: any admin can make another player an admin from the pause menu, ban players and regenerate the Game ID. Keep the list short and give it to players who are online often.

• Updates: stop, Steam Update, start, after every patch and hotfix.
• Backups: one before every update or new mod, on top of our 7 days of offsite copies.
• Restarts: at least two a day from the Scheduler, at quiet hours.
• Moving worlds: copy the world while the server is stopped, then start it and check the log.

What to Compare Before You Rent a Core Keeper Server

Core Keeper hosting offers look alike at first glance. These details decide how the server feels after a few weeks underground.

1. Slots that fit the gameCore Keeper is made for groups of up to 8, so a bigger slot count is not a bigger party.
2. Both ways to joinCheck that friends on other PC storefronts can connect directly, not only by Steam Game ID.
3. File accessYou need a file manager or SFTP to upload worlds, mods and the occasional backup.
4. RAM in the priceCheck how much memory each plan includes and what a bigger tier costs.
5. Backups you can restoreFind out whether you can roll back yourself before a major update and how long offsite copies are kept.
6. Billing termsCompare monthly and longer cycles, and look for setup fees and minimum terms.

Core Keeper Server Glossary

Dedicated server

Pugstorm's separate server program that keeps a Core Keeper world online without a host.

Steam Game ID

The code Steam players enter under Join Game to reach a server.

Direct connection

Joining with a server's IP, port and password, open to every PC storefront.

Classic world

A world from Early Access, still playable but unsupported since 1.0.

World seed

The value a world is generated from; sharing it recreates the same world.

Biome chaos

A world generation setting that controls how much biomes overlap.

The Passage

The endgame biome that surrounds the underground in 1.0 worlds.

mod.io

The mod platform Core Keeper uses alongside its Steam Workshop beta.

Core Keeper Server Help and Next Steps

Useful pages for setting up and running your world.

• More ways to play with friends using dedicated serversPugstorm on joining from every PC storefront.
• Core Keeper 1.3 patch notesEverything in Riders of the Underground.
• Core Keeper on SteamPlayer counts, platforms and system requirements.
• Gaming Deluxe control panelWhat the panel does and how to log in.
• Contact support24/7 help with worlds, mods and moving servers.