How to add mods to an Arma 3 server

Arma 3 mods add weapons, vehicles, maps and whole new systems, like ACE’s medical rules. A server runs them from its mods folder, checks players’ mods against the keys in its keys folder, and every player loads the same set in the Arma 3 Launcher.

How Arma 3 mods work

• Each mod is a folder whose name starts with @, like @cba_a3. Inside are addons with .pbo files, and usually a keys folder with a .bikey file.
• The server loads the mods named on its start line. -mod is for mods players need too. -serverMod is for mods only the server runs.
• Many mods need others. ACE, for one, needs CBA. Load the required mod first.
• Players load the same mods in the Launcher, at the same versions.

Get the mod files

The server can’t download Workshop mods itself: Workshop downloads for Arma 3 need a Steam account that owns the game, and we never use a Wilderack or customer login for that. So you upload the mods you play with:

1. Subscribe to the mods on the Steam Workshop, and let the Launcher download them.
2. Find each mod’s folder on your PC. The Launcher lists Workshop mods in your Arma 3 folder, under !Workshop. In Steam, right-click Arma 3, choose Manage, then Browse local files.
3. Copy the folders you need to one place, and rename each folder to lowercase, like @ace.

Your group’s own mods, or mods from outside the Workshop, go up the same way.

Upload and turn them on

1. Upload each mod folder to mods in Files, or over SFTP for big mods.
2. Copy each mod’s .bikey file into the server’s keys folder.
3. Open Settings, then the advanced settings.
4. In the Mods setting, list the folders with semicolons, required mods first, like mods/@cba_a3;mods/@ace.
5. Put server-only mods in Server-only mods the same way.
6. Restart.

The console shows which mods the server loaded. If one is missing, missions that need it won’t start, and the console names the missing addon.

Lowercase names on Linux

Wilderack runs the Arma 3 server for Linux. Linux treats @ACE and @ace as different names, and the server looks files up in lowercase. Keep every mod folder lowercase. If a mod still fails to load, rename the files inside it to lowercase too. A tool on your PC can rename a whole folder at once.

Signature checks

With Players may only load signed mods on, the server checks each player’s mods against the keys in keys. A player with a mod the server has no key for gets kicked. That stops changed or cheat mods, so keep it on for public servers.

If a player is kicked over signatures, check that the mod’s key is in keys and that they run the same version as the server.

Share the mod list with players

1. In the Launcher’s Mods tab, load exactly the server’s mods.
2. Export them as a preset. You get a small file listing every mod with its Workshop link.
3. Share it on your Discord. Players import it and subscribe to anything they lack.

The Launcher’s Servers tab also shows which mods your server runs.

Updating mods

When a mod updates on the Workshop, players get the new version and the server keeps the old one until you upload it. Players on the newer version may be kicked for signatures. Upload the new folder and key, then restart. Take a backup in Backups first.

Mods and memory

Big mod sets such as RHS and CUP add many gigabytes of data the server loads into memory. If you run them, see performance for the plan they need.