How to Add Mods to an Arma Reforger Dedicated Server
Mods on an Arma Reforger dedicated server are listed in the game.mods array of your server config. Each entry needs the mod's ID (modId); name is just a comment, and version pins a release. Players who join automatically download and activate the mods the server lists.
The Bohemia wiki documents the array but is thin on behavior. Where this guide goes beyond the wiki, for example on dependencies and updates, it says so and marks it as community-reported, so you know what to test on your own build (checked 2026-11-01).
- Add one object per mod to
game.mods:{ "modId": "GUID", "name": "comment", "version": "x.y.z" }. - Get the mod ID from the mod's page on the Arma Reforger Workshop, from Workbench, or from the mod's .gproj file.
- Clients automatically download and activate the listed mods when they join.
- List every dependency yourself. Community guides advise this, and the wiki does not promise the server will add them for you.
- Pin
versionfor a stable server; leave it out only if you accept updates on restart (community-reported behavior).
On this page
How game.mods works
In your server config, game.mods is an array of the mods that clients must have. This is the example from the Bohemia wiki:
"mods": [
{ "modId": "59727DAE364DEADB", "name": "WeaponSwitching", "version": "1.0.1" },
{ "modId": "59727DAE32981C7D", "name": "Explosive Goats beta", "version": "0.5.42" }
]| Field | What it is |
|---|---|
modId | The mod's GUID. Taken from the Workshop web page, from Workbench options, or from the mod's .gproj file. |
name | Has no function. It is a comment so you can tell entries apart. |
version | The mod release. The wiki lists the field without further description; see below for pinning versus tracking the latest. |
Because the config is plain JSON, a missing comma between entries stops the server from reading the file at all. Validate the file after every edit.
Step by step: add a Workshop mod
- Find the mod
Browse the Arma Reforger Workshop and open the mod's page. The mod ID is a 16-character hex code that also appears in the page address in front of the mod name.
- Note version and dependencies
On the mod's page, check the current version and whether it lists other mods it depends on. Each dependency is another mod you will list as well.
- Add the entries
In the server config, add an object for the mod and for each dependency to
game.mods. Put the mod ID inmodIdand a readable label inname. - Restart the server
Start the server and watch the log. Community guides report that the server downloads the mods on start, so the first start after adding mods typically takes longer.
- Join and verify
Join from a game client. The client should download and activate the same list automatically. Test with a second account or PC that does not already have the mods, since that is what your players will see.
Dependencies, load order and versions
Dependencies. Mods can depend on other mods, and a dependency can depend on another. The Bohemia wiki does not say the dedicated server resolves this chain for you. Community hosting guides consistently advise adding every dependency to game.mods as its own entry rather than relying on the server to find them. Do that; it costs one line per mod and removes a whole category of problem.
Load order. The wiki documents no load-order setting, and no ordering rules for game.mods. Keep each mod listed exactly once, include all dependencies, and treat order as secondary. A duplicate ID is a common mistake when merging two lists.
Versions. Hosting guides report that if you leave version out, the server uses the latest published release, and that a pinned version stays fixed until you change it. That is community-reported, so test it on your build. The trade-off is simple:
- Pinned: predictable. Nothing changes under your players until you edit the config. You have to update it deliberately, and a pinned older release must still be available.
- Unpinned: low maintenance, but a mod author can publish a release that changes your mod set between restarts.
Whichever you choose, use it consistently. A server where half the mods are pinned and half are not is hard to reason about.
Where mods are stored and how updates happen
Players: the wiki says listed mods are downloaded and activated on join. On the server, the wiki says add-ons install to the profile folder by default and that the location can be changed. The relevant launch parameters from the Bohemia startup-parameters page:
| Parameter | Purpose |
|---|---|
-profile | Sets the profile directory, which holds logs and, by default, downloaded add-ons. |
-addonDownloadDir | Sets where Workshop add-ons download. They go in an addons subfolder of that directory. |
-addonTempDir | Sets the directory for temporary content. |
-logLevel | Log verbosity: normal, warning, error or fatal. |
Do not upload Workshop mod files by hand into these folders; let the server download them. The -addonsDir and -addons parameters in the wiki are for loading local development mods together with -server, not for a normal dedicated server driven by -config.
Updates: after a mod author publishes a new release, players and the server need to agree on the version. Restart the server after you change a pinned version, then tell players to expect a download. If you run the experimental branch (app 1890870) while players are on stable, or the reverse, mods built for one game version may fail on the other, so keep server and players on the same branch.
Troubleshooting mod mismatches and failed joins
| Symptom | What to check |
|---|---|
| Server will not start after editing mods | JSON validity (missing comma or quote), duplicate entries, a typo in a modId. |
| Players cannot join or are told the mods do not match | Pinned version versus what the player has. Make sure the player's client updated to the same release, and that the pinned version is still published. |
| Mod loads for you but not for others | A missing dependency. Add every dependency to game.mods and restart. |
| Server crashes or errors on a specific scenario | A mod built for a different game version. Check the mod's page for the game version it targets. |
| Joining takes a very long time | Too many or too large mods. Remove ones that do not earn their download size. |
To find the one mod causing trouble, back up the config, then bisect: remove half the mods, restart, test, and repeat on the half that still fails. Reading the server log around the failure (see -logLevel) usually names the mod involved.
Keeping a modded server healthy
- Keep a small, known-good config as a backup, and change mods in small batches so you know what caused a problem.
- Have a staff member join a test slot after every mod change, before the community arrives.
- Write down which mod versions you pin and why, so another admin can maintain the server.
- Mods that add AI, vehicles or large scripts raise server load. Watch performance after adding them; the scenarios and performance guide covers
-logStatsand AI limits.
Hosting with ChicagoServers? The ArmA Reforger server hosting page lists what is included, such as free server backups and SFTP file access.
Frequently asked questions
Where do I find a mod ID for Arma Reforger?
On the mod's page on the Arma Reforger Workshop, where it also appears in the page address, or in Workbench options or the mod's .gproj file. It is a 16-character hex GUID.
Do I have to list mod dependencies on the server?
The Bohemia wiki does not say the server adds dependencies for you, and community hosting guides advise listing every dependency as its own entry in game.mods. That is the safest approach.
Should I pin the mod version?
Pin it if you want a predictable server that only changes when you edit the config. Community guides report that leaving it out tracks the latest release, which saves work but can change your mod set between restarts.
Do players need to install the mods themselves?
No. Per the Bohemia wiki, the mods listed in game.mods are automatically downloaded and activated when a player joins.