How to Install Mods on a Project Zomboid Server (Build 42)
Adding Steam Workshop mods to a Project Zomboid dedicated server takes three pieces of information per mod and two lines in your server config. This guide walks through the exact steps for a Build 42 multiplayer server hosted on Pterodactyl-based panels (including DoomHosting).
Build 42 note: Multiplayer is currently on the unstable branch. Many Build 41 mods do not work on Build 42 — always check the Workshop page for explicit "B42 supported" tagging before adding it.
Quick reference
| Field | Where to find it |
|---|---|
| Workshop ID | Numeric ID in the Workshop URL (e.g. ?id=2392709985) |
| Mod ID | On the Workshop description, listed as Mod ID: ExampleMod |
| Map folder name | Listed only for map mods, e.g. Map Folder: Bedford Falls |
Step 1 — Stop your server before editing
Project Zomboid rewrites both servertest.ini and servertest_SandboxVars.lua on shutdown. If you edit while it's running, your changes get clobbered. Stop the server from your panel first, then proceed.
Step 2 — Open servertest.ini in the file manager
Navigate to:
/home/container/Zomboid/Server/servertest.ini
If you renamed your server, the file uses your custom name (e.g. MyServer.ini). Open it in the panel's built-in editor or via SFTP.
Step 3 — Add the WorkshopItems and Mods lines
Find these two lines (they exist by default but are usually empty):
WorkshopItems=
Mods=
Add your IDs separated by semicolons. Example with three mods (Common Sense, Brita's Weapon Pack, ModOptions):
WorkshopItems=2685168362;2900665603;2169435993
Mods=Common Sense;Brita;ModOptions
The WorkshopItems line tells SteamCMD which mods to download. The Mods line tells the game which mods to actually load. Both must be filled in — and the order in Mods= controls load order.
Step 4 — Adding map mods
Map mods need an extra line. The Map= field controls which map the world generates from. The default (Knox County) is Muldraugh, KY. To use Bedford Falls, for example:
WorkshopItems=2392709985
Mods=BedfordFalls
Map=BedfordFalls;Muldraugh, KY
Always end the Map= chain with Muldraugh, KY so vanilla map references still resolve.
Step 5 — Recommended mod load order
Mod conflicts in Project Zomboid are common. Use this load order in your Mods= line:
- Map mods
- Tile packs (e.g.
Tile Pack v1) - Frameworks (Common Sense, ModOptions, etc.)
- Vehicle mods
- Weapon and item mods
- UI and QoL mods last
Step 6 — Save, restart, and watch the console
Save the file, then start the server. SteamCMD will download every Workshop ID listed. First-time downloads can take 5–15 minutes for a heavy modlist. Watch the console for lines like:
LOG : General , 1234567890, Mod "BedfordFalls" loaded.
If you see Mod "X" not found, double-check the Mod ID matches the Workshop description exactly — it's case-sensitive.
Where mods get downloaded
SteamCMD stores cached mods in:
/home/container/Zomboid/Workshop/
/home/container/Zomboid/steamapps/workshop/content/108600/
If a mod won't update, deleting these folders forces a fresh re-download on next start.
Players need the same mods
Both the server and every connecting player need the same mods enabled. Players who join the server are prompted to subscribe to missing mods automatically — they just have to restart the game after subscribing.
Common errors and fixes
"Mod not found in PZModFileSystem" — wrong Mod ID. Open the Workshop page, copy the ID from the description (not the title).
Server crashes on startup after adding a mod — load order is wrong, or two mods conflict. Remove the mod and check its Workshop comments for compatibility issues.
Workshop downloads stuck at 0% — SteamCMD authentication failed. Restart the server; it usually self-recovers on the second attempt.
Mod works in singleplayer but not multiplayer — many mods need servertest_spawnregions.lua updates or have explicit "SP only" notes on Workshop.
FAQ
Do I need to restart the server every time I add a mod?
Yes. Mod loading happens at boot only. Adding a mod live via /changeoption does not work for mod fields.
Can I install mods from outside the Steam Workshop?
Yes — drop the mod folder into /home/container/Zomboid/mods/ and add only the Mod ID (not the Workshop ID) to your Mods= line.
How many mods is too many? Most B42 servers run 20–60 mods comfortably. Past 80 mods, expect 2× longer boot times and higher RAM usage. Use our RAM calculator to plan accordingly.
Do mods affect server performance? Yes. Heavy gameplay mods (Brita's, vehicle expansions) add 1–3 GB RAM and can slow chunk loading. Lightweight QoL mods are essentially free.