Arma Reforger config.json Explained: Every Field, and What to Actually Change

Arma Reforger dropped the server.cfg format that Arma 2 and Arma 3 used. The Enfusion engine reads a single JSON file instead — usually called config.json — that holds everything from the UDP port to the AI cap.

That change has one practical consequence worth knowing before you open the file: JSON has no tolerance for syntax errors. A trailing comma or an unquoted string does not produce a warning and a default value. The server refuses to start, and the log line that explains why is not always obvious. Validate the file before you restart, every time.

This page walks the fields you will actually set, by category, with the default and the sane range for each. Two of the bigger ones — the mods array and the admins list — get their own pages, because there is more to say about each than a table row: see adding Workshop mods and admins and RCON.

If you would rather not hand-edit at all, our config generator builds a valid file field by field, and the config validator will catch a syntax error before your server does.

The shape of the file#

Every setting lives in one of four blocks:

{
    "region": "EU",
    "bindPort": 2001,
    "a2s": { },
    "rcon": { },
    "game": {
        "gameProperties": { }
    },
    "operating": { }
}

• Root — networking and matchmaking region.
• a2s and rcon — the query and remote-console listeners.
• game — everything a player sees: name, password, scenario, platforms, and the nested gameProperties for gameplay rules.
• operating — server-side behaviour: AI limits, save intervals, the join queue.

Network#

See Arma Reforger server ports for what each port does and which ones need to be reachable.

Query and RCON#

Set rcon.permission to monitor unless you specifically need connected clients to issue commands — most monitoring bots only need to read. Full setup is covered in admins and BattlEye RCON.

Game#

This is the block you will actually edit.

For the platform fields specifically, crossPlatform: true is what you want for a mixed PC/Xbox/PS5 group — see Arma Reforger crossplay, including the PlayStation restriction on modded servers.

Game properties#

Nested under game.gameProperties. These are the gameplay and rendering rules.

The two view-distance values are where most self-inflicted performance problems come from. serverMaxViewDistance at 10000 does not make the game look better for most players — it multiplies what the server has to simulate and stream. Raise it in steps and watch your server frame time.

Operating#

A minimal working config#

Everything omitted here takes its default. This is a public, PC-and-console, first-person Conflict server:

{
    "region": "EU",
    "bindPort": 2001,
    "rcon": {
        "port": 19999,
        "password": "changethisvalue",
        "permission": "monitor"
    },
    "game": {
        "name": "Example Milsim - Conflict Everon",
        "password": "",
        "passwordAdmin": "changethisvalue",
        "scenarioId": "{ECC61978EDCC2B5A}Missions/23_Campaign.conf",
        "maxPlayers": 48,
        "visible": true,
        "crossPlatform": true,
        "gameProperties": {
            "serverMaxViewDistance": 1600,
            "networkViewDistance": 1500,
            "battlEye": true,
            "disableThirdPerson": true
        }
    },
    "operating": {
        "aiLimit": 80,
        "playerSaveTime": 120,
        "joinQueue": {
            "maxSize": 20
        }
    }
}

What to change, in order#

If you are setting up for the first time, touch these and nothing else:

1. game.name — make it findable.
2. game.passwordAdmin — change it off the default.
3. game.scenarioId — pick your mission.
4. game.maxPlayers — match your community, not your ambitions.
5. game.crossPlatform — true if anyone is on console.
6. operating.aiLimit — cap it if you are running Conflict.
7. rcon.password — only if you want remote administration.

Come back for view distance once you have real players on the server and a frame-time graph to read.

Verify it worked#

1. Validate the file. Paste it into the config validator — this catches the syntax errors that produce a silent boot failure.
2. Restart the server and watch the log until the scenario finishes loading. A server still loading does not advertise itself.
3. Find it in the in-game browser by searching part of game.name.
4. Join, and confirm the rules you set are in effect — third person blocked, password prompted, platform mix as expected.

If step 3 fails, work through the server browser checklist before changing anything else in the config.

Trusted references#

• Arma Reforger: Server Config — Bohemia Interactive's field reference
• Arma Reforger: Server Hosting — official hosting documentation
• Arma Reforger: Startup Parameters