How to Install Mods on a FOUNDRY Dedicated Server

To install mods on a FOUNDRY dedicated server, subscribe to the mods on the Steam Workshop, copy their numbered folders from Steam\steamapps\workshop\content\983870\ on your PC into the server's Mods folder, include Unfoundry if any mod needs it, and restart the server. The server does not download Workshop mods by itself and players do not get mods on join, so everyone must subscribe to the same set. A shared Workshop collection makes that painless.

How FOUNDRY modding works

FOUNDRY has Steam Workshop support, and most mods are built with the official mod kit on top of Unfoundry, a shared library of utilities for modders. A few things follow from that:

• The server reads mods from disk. It has no Steam account and does not subscribe to anything. You give it the mod files.
• Mods do not sync. Unlike some games, FOUNDRY does not send a joining player the server's mods. A player without the same mods either fails to join or runs into errors once in the world.
• Not every mod runs on a server. Some mods only change the user interface on your own screen and have no server side. Others need to be on both sides. Read each mod's page.

Step 1: Pick your mods and build a collection

Choose your mods on the FOUNDRY Workshop, then make a Steam Workshop collection with all of them, including Unfoundry if any of them list it as a requirement. A collection gives you a single link for the group, and a single list for you to compare against the server.

Commonly used mods include:

Start small. Two or three mods on a fresh server are easy to debug. Twenty mods added at once make it very hard to tell which one broke the world.

Step 2: Get the mod files on your PC

1. Subscribe to every mod in your collection in Steam.
2. Launch FOUNDRY once so Steam downloads them. The Workshop page notes that some games need a relaunch before an item downloads.
3. Open Steam\steamapps\workshop\content\983870\. The default Steam path is C:\Program Files (x86)\Steam, unless you installed Steam or the game to another drive.

Each mod is a folder named with its Workshop ID, a long number. That number is also in the mod's Workshop page address, so you can tell which folder is which.

Step 3: Back up and stop the server

Mods that add new machines or items change what is saved in your world. If you later remove such a mod, the world may refuse to load. So:

1. Take a backup. On GamezServers that is one click in the panel.
2. Stop the server.

Step 4: Upload the folders into Mods

Copy each numbered mod folder, as a whole folder, into the server's Mods directory in the server's root. The result should look like this:

Mods/
  3297627927/      <- Unfoundry
  1234567890/      <- another mod
  9876543210/      <- another mod

Keep the folder structure exactly as Steam made it. Do not pull files out of the numbered folders, and do not rename them.

On our servers, use the file manager to create the Mods folder if it does not exist yet, then upload the folders over SFTP. SFTP is faster and keeps folder structure intact for mods with many files.

Step 5: Start and check the console

Start the server and watch the console while it loads. Look for errors or exceptions that mention a mod, and check that the server finishes loading the world. On GamezServers the live console in the panel shows this as it happens.

If a mod fails:

• Unfoundry missing. The most common cause. Add the Unfoundry folder and restart.
• Client only mod. It has nothing to do on a server. Remove its folder from the server, and players can still use it locally if it does not affect the world.
• Outdated after a game patch. FOUNDRY is in Early Access and patches change things mods depend on. Wait for the mod author's update or remove it for now.

Step 6: Get every player on the same mods

Send the group your collection link. Each player clicks Subscribe to all, starts the game once so the mods download, and then joins with Multiplayer, IP Direct Connect.

After that, keep the server and players in step:

1. When a mod updates on the Workshop, players get the update automatically through Steam.
2. The server does not. Copy the updated folder from your PC to the server again, replacing the old one, and restart.
3. If players get errors right after a mod update, this mismatch is almost always why.

Removing a mod safely

Removing is riskier than adding.

1. Take a backup first.
2. Check the mod's page for removal notes. Mods that add items or machines often say to remove everything they placed before uninstalling.
3. Stop the server, delete the mod's folder from Mods, and start again.
4. If the world fails to load, restore the backup and put the mod back.

Then remove it from the collection and tell players to unsubscribe.

Do mods slow the server down?

Small quality of life mods cost very little. Mods that add lots of new machines and recipes make an already large factory bigger, and the server's memory grows with the factory and the voxel world players have dug out. If a heavily modded mid game factory starts stuttering, more memory helps. Our FOUNDRY plans start at 8 GB for a small group, with 12 GB and 16 GB for bigger factories, and you can change plans in the panel at any time.

Common problems

If the server will not show in the list at all after you add mods, that is usually a separate issue: see FOUNDRY server not showing in the server list.

The easy way to run a modded factory

A FOUNDRY server from GamezServers gives you a file manager and SFTP for the Mods folder, a live console to watch mods load, and one click backups before every change. Pause Server When Empty, the map seed, autosave interval, player cap and public listing are panel settings, and it is live within about a minute of paying. For the full self hosted setup, see how to host a FOUNDRY server.

FAQ

Where do FOUNDRY Workshop mods download to?

To Steam\steamapps\workshop\content\983870\ on your PC, one folder per mod, named with its Workshop ID.

Do players need the same mods as the FOUNDRY server?

Yes. Mods do not download when you join, so every player must subscribe to the same mods, ideally from one Workshop collection.

Do I need Unfoundry on the server?

If any of your mods depend on it, yes. It is the library most FOUNDRY mods are built on, so most modded servers have it.

Can I add mods to an existing FOUNDRY world?

Yes. Back up first, then add the mod folders and restart. Removing mods later is the risky part.

Why did my mods stop working after an update?

FOUNDRY is in Early Access and patches can break mods until their authors update them. Update the mod folders on the server, or remove the mod until a fix is out.