Arma Reforger SteamCMD Builder

What is SteamCMD?

SteamCMD is Valve's command-line Steam client, built specifically for installing and updating dedicated game servers. It downloads the same files as the regular Steam client but runs headless — perfect for Windows batch scripts, Linux cron jobs, or one-click deployments on a VPS. For Arma Reforger, SteamCMD fetches the server binary from app 1874900; mods are pulled separately by the server itself from reforger.armaplatform.com, not from Steam Workshop.

Arma Reforger Server App IDs

Use 1874900 in every app_update command. Never run workshop_download_item — that is Steam Workshop, and Reforger uses its own workshop protocol.

Stable vs Experimental Branch

Bohemia publishes two branches of the Arma Reforger server binary. Stable is the default — it matches what public players run. Experimental is where upcoming patches land one to two weeks before stable, so modders and community server operators can catch regressions early.

Clients on stable cannot connect to experimental servers and vice versa. If you flip branches, warn players in advance — their client needs to switch too.

Update vs Fresh Install

SteamCMD does not maintain a global install registry — it tracks installed builds per install directory. That makes force_install_dir mandatory on every invocation. Point it at the same path you used for the original install and SteamCMD will fetch only the changed files. Point it at a new path, or omit it entirely, and SteamCMD will re-download the whole ~12 GB server because, from its perspective, this is a brand-new install.

The fix is simple: always call force_install_dir before login anonymous, and store the path in a variable at the top of your script so you cannot typo it later.

SteamCMD Command Reference

Tip: Use the + prefix (e.g. +login anonymous) when chaining on a single shell line; omit it inside an interactive SteamCMD prompt.

Frequently Asked Questions