{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "type": "object",
    "patternProperties": {
        "^[0-9a-zA-Z_-]{1,255}$": {
            "type": [
                "string",
                "number",
                "boolean",
                "null"
            ]
        }
    },
    "additionalProperties": false
}