The Arma Reforger server config JSON explained

Arma Reforger keeps things in one place: the entire server configuration is a single JSON file. That rigidity is a feature — there is only one thing to look at — but it forgives nothing.

Identity fields

Name, description and optional password decide what players see in the browser. Two things worth knowing: a server with no password is open to anyone who finds it, and a clear name does more for filling slots than most people expect.

The scenario

This is the most consequential field. It decides which game mode loads at startup: Conflict, Game Master, or a custom scenario from a mod. An approximate reference gives you a server that starts on something else entirely, with no error — easily the most common trap.

Slots

Arma Reforger imposes no artificial cap: you set whatever the machine and the network can carry. But it is not a free number. Load on an Enfusion server rises sharply during large engagements, and a server advertised at a hundred that stutters at sixty loses more players than an honest sixty-slot server.

Mods

Mods are declared in the JSON by Workshop ID and version. Two consequences:

• An approximate ID is silently ignored. The server starts without the mod and you only find out in-game.
• Pinning the version protects you from an author update that changes your balance overnight.

Gameplay settings

Third-person view, map markers, friendly fire, revive rules: these decide whether your server is mainstream or milsim. They deserve to be settled before you open, because changing them afterwards splits the community that already moved in.

What stops the server from starting

• A missing or extra comma. The server exits immediately. Running the file through a JSON validator before restarting saves a lot of time.
• A required field left out. Same result, clearer message.
• Editing the file while the server runs. The JSON is only read at startup.

Our Arma Reforger hosting gives direct access to the file, which means you can validate it before restarting rather than discovering the error in the logs.