Add multiple Metafields to a Shopify Product in one API call

metafields.json

// PUT https://yourstorename.myshopify.com/admin/products/#{id}.json
{
  "product": {
    "metafields": [{
      "namespace": "your_namespace",
      "key": "your_key",
      "value": "your_value",
      "value_type": "string"
    },
    {
      "namespace": "your_namespace",
      "key": "your_key",
      "value": "your_value",
      "value_type": "string"
    },
    {
      "namespace": "your_namespace",
      "key": "your_key",
      "value": "your_value",
      "value_type": "string"
    },
    {
      "namespace": "your_namespace",
      "key": "your_key",
      "value": "your_value",
      "value_type": "string"
    }]
  }
}