{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "type": "object",
    "properties": {
        "id": {
            "type": "string",
            "description": "The message id"
        },
        "content": {
            "type": "string",
            "description": "The message content"
        },
        "meta": {
            "type": [
                "object"
            ],
            "properties": {
                "creator": {},
                "created": {
                    "type": [
                        "string"
                    ],
                    "description": "The subject creation date"
                },
                "updated": {
                    "type": [
                        "string"
                    ],
                    "description": "The subject update date"
                }
            }
        }
    }
}