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How to Install Mods on a Project Zomboid Server

Add Steam Workshop mods and map mods to your Project Zomboid server — Workshop IDs, Mod IDs, load order and fixes for common errors.

How to Install Mods on a Project Zomboid Server

A Project Zomboid server downloads Steam Workshop mods by itself: you tell it which Workshop items to fetch and which mods inside them to turn on, restart it, and every player who joins gets the same mods automatically. This guide shows where those settings live on a Lobby Maker server and how to avoid the mistakes that stop a modded server from starting.

Make a backup first (Backups tab). A broken mod list can stop the server from loading your world, and a backup takes seconds to restore.

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1. Find the Workshop ID and the Mod ID

Every mod needs two values, and they are not the same thing:

  • Workshop ID — the number at the end of the mod's Steam Workshop address. In https://steamcommunity.com/sharedfiles/filedetails/?id=1234567890 it is 1234567890.
  • Mod ID — the mod's internal name. Authors list it at the bottom of the Workshop description as Mod ID: .... One Workshop item can contain several Mod IDs (a main mod and optional add-ons, for example) — enable only the ones you want.

Map mods also list a Map Folder on their Workshop page. Keep all three lists in a notepad; you will paste them in step 3.

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2. Open your server's config file

1. Open your server in the panel (My game servers → Server Panel). 2. Stop the server from the Console tab. Project Zomboid rewrites its config when it shuts down, so changes made while it runs can be lost. 3. Go to the Files tab and open the .cache/Server/ folder. 4. Open the .ini file named after your server — the Server Name from the Startup tab (for example MyServer.ini).

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3. Add the mods

Find these two lines and fill them in. Separate the entries with semicolons, without spaces:

WorkshopItems=1234567890;2345678901
Mods=ExampleMod;ExampleLibrary
  • WorkshopItems= takes the Workshop IDs — what the server downloads.
  • Mods= takes the Mod IDs — what the server turns on.

Every Mod ID must belong to a Workshop item listed in WorkshopItems=. A mod that other mods depend on (a "library" or "framework") should come before them in Mods=.

Map mods

Map mods need one more line. Put the custom map folders first and keep the vanilla map last:

Map=ExampleMapFolder;Muldraugh, KY

Click Save Content, then Start the server from the Console tab.

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4. Check that the mods loaded

The first start after adding mods takes longer: the server downloads every Workshop item before it loads the world. Watch the Console tab — you will see the Workshop items being downloaded, then the mods being loaded, and finally the line that the server has started.

Players don't need to subscribe to anything in advance: when they join, the game offers to download the server's mods. They only need to run the same game build as the server (Build 41 or Build 42).

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Common problems

"Workshop item version is different than server's" when joining. A mod was updated on the Workshop after your server downloaded it. Restart the server so it fetches the new version; players may need to restart their game as well.

A mod is listed in `WorkshopItems=` but does nothing. Its Mod ID is missing from Mods=, or it is misspelled — Mod IDs must match exactly, including capital letters.

The server crashes right after loading a mod. The mod is made for another game build: Build 41 and Build 42 mods are not interchangeable. Check the Workshop page, remove the mod from both lines and start again.

My changes disappeared. The server was running while you edited the file and overwrote it when it stopped. Stop the server first, then edit.

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Frequently asked questions

How many mods can a server run? There is no fixed limit, but every mod adds loading time and memory use. Big collections (50+ mods) need a plan with more RAM.

Can I add a whole Steam Workshop collection? Not in one go — add the Workshop IDs of the items in the collection to WorkshopItems= and their Mod IDs to Mods=.

Will adding mods reset my world? No, your save stays. Removing a mod that added items or buildings can break them in the world, so make a backup before removing mods.

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Don't have a server yet? Rent a Project Zomboid server on Lobby Maker — it is ready in about a minute, and mods work exactly as described above.