How to Use No-Steam Mode
By default, Project Zomboid servers use the Steam Workshop and Steam Networking (P2P) for connectivity. Working in No-Steam Mode (using the -nosteam flag) allows players from other platforms like GOG to join your server and allows for a completely DRM-free experience.
Note: Enabling this mode changes how networking and mods work significantly. The server will no longer automatically download Workshop items.
Why use No-Steam Mode?
- GOG Crossplay: Allow friends who own the game on GOG to join.
- Offline Play: Run a server on a local network without an internet connection.
- Version Control: Prevent mods from updating automatically and breaking your save file.
- Privacy: Your server will not appear on the Steam global server list.
Server-Side Setup
1. Enable the Flag
The server has to be launched with -nosteam. How you set that depends on where the server runs.
On a Supercraft server
There is a setting for it, so there is no script to edit:
- Open your server in the panel and go to Configuration.
- Open the Advanced section.
- Turn on No-Steam mode (GOG crossplay) and save.
- Restart the server. The setting only takes effect on the next start.
Read the three trade-offs next to the setting before you turn it on: one-click Workshop mods stop being applied, the panel and your public page stop showing the live server name, map and player count, and bans by Steam ID stop working. Bans by username, the whitelist and access levels are unaffected.
On your own machine
Add the flag to the launch command. On Build 41 that means editing the start script:
./ProjectZomboid64 "$@" -nosteamBuild 42 launches the jar directly and has no script to edit, so pass -nosteam as a server argument instead.
2. Ports
In Steam mode, Steam brokers the connection. In No-Steam mode players connect straight to your address, so the ports have to be reachable:
- 16261 (UDP): Main game port.
- 16262 (UDP): Direct connection port.
On a Supercraft server both are already open, and your panel shows the address and port to hand out. On a home server you have to forward them on your own router.
Managing Mods Manually
This is the most difficult part of No-Steam mode. Since the server cannot "talk" to the Steam Workshop, you must provide the mod files yourself.
- Download the mods from the Workshop on your local PC.
- Navigate to your local Steam Workshop folder:
SteamLibrary\steamapps\workshop\content\108600\ - Upload the folders (named by their Workshop ID) to the server's
Zomboid/mods/directory. On a Supercraft server that is the Mods folder in the File Manager, and you can also reach it over FTP. - In your
servertest.ini, you must still list the Mod ID in theMods=line, but theWorkshopItems=line will be ignored.
Client-Side Setup (Joining)
Players on Steam must also launch their game in No-Steam mode to connect to a No-Steam server.
- Right-click Project Zomboid in your Steam Library.
- Select Properties -> General.
- In Launch Options, type:
-nosteam - Launch the game.
Troubleshooting
| Issue | Solution |
|---|---|
| "Connection Failed" | Ensure both server AND client are running with the -nosteam flag. Verify ports are open. |
| Live server info is blank | Panels read the server name, map and player count over the Steam query protocol, and in No-Steam mode nothing answers it. On Supercraft the server still shows as running, but those live fields stay empty. Join by IP as normal. |
| "Workshop item version mismatch" | This usually happens if you have Workshop IDs listed in the .ini while in No-Steam mode. Clear the WorkshopItems= line and use manual mods. |
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