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Set up a dedicated Project Zomboid server (Build 42)

Now that Build 42 multiplayer has reached the stable branch, a dedicated server is the simplest way to keep a world alive between sessions: it runs without leaving your PC on, and you only pay for the hours it actually runs.

1. Create the server

Pick Project Zomboid, the amount of RAM and the sandbox preset. The server starts on its own, and you get a stable connection address to share with your group.

2. The sandbox preset

Apocalypse is the default — the hardest one, the classic campaign settings. The others available: Survivor, Survival, Builder, FirstWeek, SixMonthsLater and Beginner.

⚠️ The preset is chosen at creation and cannot be changed afterwards: it defines the world itself. To try another one, create a second server.

3. Join the game

In game: Play → Join → Add server, then paste the address and password shown in your console.

There are no ports to forward: the game ports (16261 and 16262 over UDP) and the Steam ports (8766 and 8767) are already handled. Older tutorials asking you to open a whole range, one port per player, predate 41.65 — that requirement is long gone.

4. Mods, without the usual trap

A Project Zomboid server needs two different lists, and mixing them up is the number one reason a server refuses to start:

  • WorkshopItems= — the Steam IDs of the mods (the numbers you see in the Workshop URL);
  • Mods= — the internal IDs, written inside each mod's mod.info file, which have nothing to do with the ones above.

Here, you only fill in the first list. On the first start the server downloads the mods, we read the downloaded mod.info files, derive the internal IDs and restart the server with the right configuration. If nothing could be downloaded, we refuse to start rather than quietly booting a vanilla world — that is the kind of surprise you discover three evenings later.

⚠️ Build 41 mods do not work on Build 42: the modding system was rebuilt and every mod has to be ported by its author.

5. The settings, and when they take effect

The sandbox preset (§2) is the only setting locked at creation. The others can be changed from the console, and take effect on the next start: they are injected into the machine at boot, not applied live.

Setting Default What it does
PvP on Allows players to fight each other. Turn it off for a strictly co-operative game.
Pause when nobody is playing on Freezes world time while the server is empty (see §7).
Visible in the public list off While this is off, the server does not show up in the game's public browser: you get in with the address and password only.
Steam Workshop mods empty The Steam IDs of your mods (see §4).

Everything else — fine-grained difficulty, season length, zombie density, how long before water and power shut off — does not come from these settings but from the preset you picked at creation. Those values live in the server's sandbox variables, next to its Server/tickserv.ini file; both are readable from the file manager.

6. How much RAM?

  • A group getting started, few or no mods: 8 GB.
  • Large group, or a lot of mods: 16 GB.

The part most guides leave out: memory use grows as you explore. A three-week-old world with a widely explored map and built-up bases is significantly heavier than a fresh one. You can move up a tier whenever you need to, without losing your game.

7. Time passes while you're away

On a server left running around the clock, the world keeps ageing while nobody plays: power and water eventually shut off (two in-game weeks by default), crops wither, generators run dry, food spoils.

Two protections are on by default: pause when nobody is connected (time stops while the server is empty), and above all the fact that a stopped server ages nothing at all. You come back to the world exactly where you left it, even three weeks later.

8. Your saves, and how to bring an existing world over

The world is saved on shutdown and restored on the next start. On top of that, a timestamped backup is taken every 30 minutes while the server runs, and the last five are kept. You can download them, or restore one — with the server stopped, so you never overwrite a world that is being written to.

Already have a game running elsewhere? You can bring it over:

  1. Grab the Zomboid/Saves/Multiplayer/<ServerName>/ folder from the machine that was hosting.
  2. Zip that folder — or just its contents, we put it in the right place either way.
  3. Upload the archive when you create the server.

⚠️ A Build 41 save will not load on Build 42: the formats are incompatible, and nothing converts one to the other.

9. Shut down when you're done

Server off = €0. Auto-shutdown kicks in on its own when nobody is connected, the world is saved on shutdown and restored on the next start.

Create your Project Zomboid server

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