Project Zomboid mods come from the Steam Workshop, and the server downloads them for you. You don't upload any files. You tell the server which mods you want in its config file, and players who join download them automatically. They don't need to subscribe to anything themselves.
Every mod has two IDs
You need both, and they go in different places.
- The Workshop ID is the number at the end of the mod's Steam Workshop address, after
?id=. It tells the server what to download. - The Mod ID is the name the mod gives itself. Authors usually list it near the bottom of the Workshop description, as
Mod ID: something. It tells the server what to load.
One Workshop item can contain several mods, each with its own Mod ID. Downloading an item doesn't turn on anything inside it, so only add the Mod IDs you want.
Also check the Required items box on each Workshop page. Those mods (usually libraries) need adding too. A missing library is the most common reason a mod downloads but doesn't work.
Adding the mods
- Stop the server from the Console tab in the panel.
- Open the Files tab and go to the
.cache/Serverfolder. Your server's config file is in there, calledservertest.iniunless you've renamed the server. If you're using SFTP and can't see.cache, turn on hidden files in your client. Folders whose names start with a dot are hidden by default. - Find the
WorkshopItems=line and add the Workshop IDs, separated by semicolons with no spaces:WorkshopItems=2875848298;2886832257 - Find the
Mods=line and add the Mod IDs the same way. On Build 42, put a backslash before each one:Mods=\damnlib;\BB_CommonSenseOn Build 41, leave the backslashes out:Mods=damnlib;BB_CommonSense - Put libraries and other required mods before the mods that need them.
- Save and start the server. The first start takes longer while it downloads everything, and you can watch that happen in the console.
Mod IDs are case-sensitive, so copy them exactly.
Map mods
A map mod needs a third line. Add its Workshop ID and Mod ID as above. Then add the map's folder name (the author lists it on the Workshop page) to the Map= line, in front of the base game map:
Map=YourMapFolder;Muldraugh, KY
Keep Muldraugh, KY last.
Build 41 or Build 42?
Mods are made for a particular build. A Build 41 mod generally won't work on a Build 42 server, and the other way round. Check that every mod's Workshop page supports the build your server runs, and that your players are on the same build as the server.
Before you change mods on an existing world
Some mods aren't safe to add or remove partway through a save. Before you change anything, download a copy of your world and change one mod (plus its dependencies) at a time. Then if something breaks, you know which mod caused it.
Keeping mods up to date
When a mod updates on the Workshop, players can't join until the server has the same version. Restart the server and it downloads the update. If you're an admin in-game, /checkModsNeedUpdate checks whether any mod has changed and writes the answer to the server log.
If a mod isn't working
- Players aren't asked to download anything: the Workshop ID is missing or wrong in
WorkshopItems=. - The mod downloads but doesn't do anything: its Mod ID is missing from
Mods=, or a required library is missing. - The map loads but the world is the normal one:
Map=isn't set, or the folder name is misspelled. - "Workshop item version is different": the mod updated. Restart the server, and have the player restart Steam.