{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "description": "An array of key-value pairs that represent Apple HealthKit metadata information.",
    "type": "array",
    "references": [
        {
            "description": "A general description of metadata in HealthKit.",
            "url": "https://developer.apple.com/library/ios/documentation/HealthKit/Reference/HKObject_Class/index.html#//apple_ref/occ/instp/HKObject/metadata"
        }
    ],
    "items": {
        "type": "object",
        "properties": {
            "key": {
                "description": "A predefined or custom metadata key. Use Apple defined keys, e.g. HKMetadataKeyDeviceSerialNumber, when possible.",
                "type": "string",
                "references": [
                    {
                        "description": "The list of predefined metadata keys in HealthKit.",
                        "url": "https://developer.apple.com/library/ios/documentation/HealthKit/Reference/HealthKit_Constants/#//apple_ref/doc/constant_group/Metadata_Keys"
                    }
                ]
            },
            "value": {
                "oneOf": [
                    {
                        "type": "string"
                    },
                    {
                        "type": "number"
                    },
                    {
                        "type": "boolean"
                    }
                ]
            }
        },
        "required": [
            "key",
            "value"
        ]
    }
}