Core Keeper server hosting: the complete guide
Core Keeper is a slow-progress game: you dig, you set up a base, you come back three evenings later. That is exactly the kind of run that suffers when it depends on one player's PC. A dedicated server keeps the cavern alive between sessions, and is only billed while it runs.
1. Create the server
Pick Core Keeper, the RAM and the performance level. The server starts on its own; you get a stable connection address and a password to share.
Two choices are made at creation and cannot be changed afterwards: the world mode and the seed.
2. World mode, decided once and for all
| Mode | What it changes |
|---|---|
| Normal | The game's default balance. |
| Casual | Weakened enemies — for exploring and base-building. |
| Hard | Tougher enemies, less room for error. |
| Creative | Every item unlocked, no resource constraints. |
⚠️ The game cannot move a world from creative to non-creative, nor the other way round, nor change difficulty after the fact. The mode is written into the world when it is created. To try another one, create a second server — the first costs nothing while it is off.
The seed follows the same rule: left empty it is random; filled in, it gives back exactly the same cavern.
3. Joining the game
Two routes, and it is worth knowing which to use.
- By address — in game, enter the IP address and port shown in your dashboard, then the password. That is the direct route, and it works from any platform.
- By game code — Core Keeper also shows a session code, which you will find in your dashboard. That is the simplest route for players on a games console, who have no address field to type into.
You have no ports to open: the game port (27015) and the Steam query port (27016) are already in place.
One detail that matters: our servers are configured for direct connection, not only through the Steam relay. Without that, a Core Keeper server literally has no reachable IP address — it is the default behaviour of the official image, and the reason some hosts only ever hand you a game code.
The server takes 8 players by default, up to 10.
4. Seasonal events, forced or not
By default the server follows the real date: Easter, Halloween, Christmas, Valentine's, the game's anniversary, cherry blossom and Lunar New Year arrive when they arrive.
You can force an event — play Halloween in June — or turn them all off. That setting can change at any time; it takes effect on the next start.
5. Mods
Our Core Keeper servers run vanilla. The game has no official server-side mod loader, and community solutions bind to one precise game version — a server that updates itself would break them without warning.
6. How much RAM?
Core Keeper is a Unity game with a map that grows as you explore: memory rises with the area you have uncovered, not with the number of players.
| Your game | What we suggest |
|---|---|
| Early run, group of 2 to 4 | 4 GB, eco tier |
| Well-explored cavern, full group | 8 GB, eco tier |
| Long campaign, heavily built base | 8 GB on dedicated CPU |
The price follows the RAM and the performance level, never the game.
One thing to know about starting up: the game is not baked into the image — it is re-downloaded from Steam every session, since the machine is new. The first start of an evening is therefore slower than waking a server someone left idling elsewhere. That is the price of "€0 when off": we genuinely destroy the machine.
7. Renaming your server does not lose your world
The server name can be changed whenever you like. The save, though, is indexed by its number (worlds/0.world.gzip) and not by the name — so renaming is safe. It is a classic trap elsewhere: on other games, changing the server name makes the run "disappear" because the save path depends on it.
8. Your world is kept between sessions
The world is saved on shutdown and restored on the next start, at no cost. A timestamped backup is taken regularly while the server runs, and the most recent one is kept; the backup option keeps several, staggered over several days back.
Already have a cavern going? Bring it over:
- Get the
worlds/<n>.world.gzipfile from the server's data folder (core-keeper-data). - Put it at the root of the archive, with no folder around it.
- Upload the archive when you create the server. One world per server: if the archive holds several, we keep the most advanced one.
9. Shut down when you're done
Server off = €0. Auto-shutdown kicks in on its own once nobody is connected. On a game played in waves — one intense weekend, then three weeks of nothing — that is where the gap with a monthly plan opens up.