Arma Reforger Config.json Validator
Paste or upload your Arma Reforger server config.json to check JSON syntax, required fields, duplicate mods, invalid Workshop IDs, and common server configuration problems.
Validation runs entirely in your browser; your config is never uploaded. The optional Workshop check sends only mod IDs to the API.
What this validator checks
JSON syntax first, then the structure the dedicated server expects: required fields, types and ranges, port conflicts, scenario ID format, duplicate Workshop IDs, malformed mod entries, and settings that commonly stop a server from starting.
Common Arma Reforger config errors
Trailing commas and smart quotes from a word processor, a scenarioId missing its {GUID} prefix, bindPort colliding with the A2S port, mods listed with a name but no modId, and the same Workshop ID listed twice.
Nothing is uploaded
Validation runs entirely in your browser. The file is never sent to our servers. Workshop IDs are only resolved against the public API if you ask for it, and only the IDs are sent.
Related tools
Building the file rather than checking one? Use the Config Generator. Only the mod list? Use the Mod Manager.
Frequently asked questions
Is my config uploaded anywhere?
No. Syntax and structure validation runs entirely in your browser. If you choose to check mod IDs against the Workshop, only the mod IDs are sent to the API, never the rest of your config.
What does the validator check?
JSON syntax with line positions, the overall config structure, port ranges, required game fields like scenarioId, and the game.mods array including duplicate or malformed mod IDs. It does not enforce rules that are not publicly documented.
My config is valid but the server still fails to start. Why?
A structurally valid config can still reference a missing scenario, an unavailable mod version, or a port that is already in use. The troubleshooting guide on this site covers the most common startup failures.