The complete guide · 6 min read
The Complete Guide to Foundry Server Hosting
A practical walk through running a FOUNDRY world on a dedicated server: why it helps a co-op team, the app.cfg file key by key, slot and memory choices, worlds and seeds, updates through Early Access, Workshop mods and how players connect. Written for whoever ends up being the team's server admin.
By Matthew Griffin, Owner, Gaming DeluxePublished · Updated
In this guide
- Why a Factory Game Benefits from a Dedicated Server
- Configuring the Server with app.cfg
- Choosing a Slot Count and Memory Size
- Worlds, Seeds and Save Folders
- Updates Through Early Access
- Workshop Content and the Mod Kit
- Ports and How Players Join
- What to Compare Before Renting a Foundry Server
- Foundry Server Glossary
- Foundry Server Help and Further Reading
Why a Factory Game Benefits from a Dedicated Server
Automation games reward patience. You plan a smelting line, wait for ore to flow, then spend the next session expanding it. In a hosted co-op game that rhythm breaks whenever the person who owns the save is away, because the world only exists while their copy of FOUNDRY is running. Everyone else has to wait, or play on a separate world that never joins up with the shared one.
Channel 3 Entertainment publishes a separate program for this, listed in the Steam Tools library as FOUNDRY: Dedicated Server. It runs the world on its own, without anyone playing on that machine. You can run it on a home PC, but that PC then has to stay switched on, keep two ports open on your router and push every player's traffic through your home upload. A hosted server moves that job to a data centre with a fixed address, DDoS filtering and staff on hand at any hour.
The other benefit is fairness. When the world lives on a neutral server, nobody's PC carries the extra load of hosting while also playing, and the night owl in the team can tidy the logistics while the early risers are asleep.
Configuring the Server with app.cfg
The official dedicated server page explains that settings go in a file called app.cfg, created in the same folder as FoundryDedicatedServer.exe. At home you would then start the server with FoundryDedicatedServerLauncher.bat. On Gaming Deluxe the panel starts the server for you, and app.cfg opens in the browser config editor. These are the keys the official page lists:
| Key | Purpose | Default or example |
|---|---|---|
| server_name | Name players see in the server browser | Your choice |
| server_password | Keeps the world private | Optional |
| server_world_name | Name of the save folder to load | Your choice |
| pause_server_when_empty | Stops the simulation with nobody online | true or false |
| autosave_interval | Seconds between automatic saves | 300 in the example |
| server_is_public | Lists the server publicly | true or false |
| server_port | Game connection port | 3724 |
| server_query_port | Port the browser queries | 27015 |
| mapseed | Seed for a newly generated world | Any seed |
| server_max_players | How many can be connected at once | 32 in the example |
| server_persistent_data_override_folder | Moves where saves are stored | Leave as set by us |
Choosing a Slot Count and Memory Size
Paradox's FAQ describes FOUNDRY as designed towards 2 to 4 players on one server, while stating there is no hard limit. The example app.cfg on the official server page uses 32 for server_max_players, and our order form slider runs from 8 to 32. Any whole number in between can be chosen.
For a regular group of friends, the 8 slot card is the obvious start: it leaves spare seats for guests and bundles 5GB of RAM. Bigger communities can step to 16, 24 or 32 slots, which come with 8GB, 12GB and 16GB. Those memory sizes are our own judgement, because no official RAM or CPU figures are published for the server.
Memory use in factory games tends to follow the size of the build. A world with long conveyor runs, dozens of assemblers and a train network spanning the map simply has more to keep track of. Watch the memory graph in the panel during a busy evening. If it hovers near the ceiling, move up a tier from the client area; the order form offers up to 32GB, and the change keeps your save.
Remember too that FOUNDRY is in Early Access. Performance with very large groups depends on the build of the day, so if you plan a big public world, start sensibly and grow the plan once you see how the server copes.
Worlds, Seeds and Save Folders
Two keys decide which world the server runs. server_world_name holds the name of the save folder the server works with, so keep it the same to stay on the same world. mapseed only matters when a fresh world is generated, so settle on it before the first start.
On a Windows PC running the dedicated server, saves land under C:\Users\%USER_NAME%\AppData\LocalLow\Channel 3 Entertainment\FoundryDedicatedServer\save. On our servers the panel's File Manager shows the equivalent folder, and SFTP is the quickest way to pull a copy down to your own machine.
- Stop the server from the panel.
- Take a snapshot in Backup Manager.
- Upload the world folder you want into the save directory.
- Set server_world_name to that folder's name in app.cfg.
- Start the server and check the Web Console as it loads.
Those steps are a general approach, not an official procedure. The official page does not document moving a single-player save to a server, so we cannot guarantee it for every world. Our team is happy to try it with you.
Updates Through Early Access
FOUNDRY has been in Early Access since 2 May 2024 and receives large numbered updates. The most recent, Foundry 4.0 Rails and Reactors on 28 April 2026, brought trains, the Xeno Power Plant, an info overlay, a construction drone, new robots for assembly lines, neon decor and a modular casting machine. Hotfix #2 followed on 4 May 2026.
Channel 3's DevBlog #113 on 2 October 2026 previewed what comes next: blueprints, new loaders, conveyor lifts and train improvements. There is no date for that update, nor for version 1.0, which DevBlog #112 says the team is heading towards.
Whatever the patch, one rule holds: the official server page says the server and the game must run the same version. When Steam updates the game on your PC, run Steam Update in our panel and restart. Snapshot the world first if the patch notes mention big changes, so you have a way back if something behaves oddly.
Workshop Content and the Mod Kit
Update 1, Cable and Creations, released on 13 August 2024, opened FOUNDRY to modding with three things: Steam Workshop support, a Workshop uploader and the Foundry Mod Kit, which is a Unity project modders use to build new content.
- Keep the whole team on the same mod list, just as everyone must share the game version.
- Read each mod's Workshop page for notes on multiplayer or dedicated servers, since official notes do not cover every case.
- Back up before adding or removing a mod, so you can return to a clean copy if the world misbehaves.
Ports and How Players Join
The dedicated server listens on a game port, 3724 by default, and a query port, 27015 by default, which answers the Steam server browser. At home both would need forwarding; on our servers they are open already and Server Details shows the address.
Players can join in two ways. With server_is_public enabled, the world appears in the Steam server browser. Otherwise, or as a shortcut, they open Multiplayer, pick IP Direct Connect and type the address and port. Add server_password if you want only your team inside.
What to Compare Before Renting a Foundry Server
A few checks that show whether an offer will still suit you once the factory grows.
- Flexible slot countsThe game has no hard player cap, so a slider that lets you pick the exact size saves paying for empty seats.
- Bundled memorySee how much RAM the base price covers and what each extra tier costs once your world gets big.
- Direct app.cfg accessYou should be able to edit every key yourself, including the pause, autosave and visibility settings.
- Quick version updatesCheck that you can update the server yourself the moment a patch lands, since mismatched versions block joins.
- Self-service restoresAsk how many days of offsite backups are kept and whether you can restore without waiting on a ticket.
- Terms and feesCompare cycle discounts and look for setup charges or minimum periods.
Foundry Server Glossary
- FOUNDRY: Dedicated Server
- Channel 3's standalone program, in the Steam Tools library, that hosts a world without a player.
- app.cfg
- The plain settings file beside the server exe that holds name, password, world, ports and more.
- server_world_name
- The save folder name the server loads or creates.
- mapseed
- The value used to generate a new world's terrain.
- Autosave interval
- Seconds between automatic saves, set with autosave_interval.
- Query port
- The port the Steam server browser asks for server info, 27015 by default.
- IP Direct Connect
- The Multiplayer menu option for joining a server by address and port.
- Foundry Mod Kit
- The official Unity project used to make Workshop mods.
Foundry Server Help and Further Reading
Official pages and our own guides for running your world.
- Official FOUNDRY dedicated server pageApp.cfg keys, ports and save locations.
- FOUNDRY FAQ, Paradox InteractivePlayer counts and platforms.
- FOUNDRY news on SteamPatch notes and DevBlogs.
- Gaming Deluxe control panelLogging in and finding your way around.
- Contact supportHelp with configs, worlds and updates at any hour.
About this guide: built from Channel 3's official dedicated server page, Paradox's FOUNDRY FAQ, Steam patch notes and DevBlogs, written with AI help, matched against our live order form for slots, prices and locations, and reviewed by Matthew Griffin. Notice something outdated? Let us know.
Sources, checked October 21, 2026: