query PreviewEmailTemplate($type: String!, $recipientType: String!, $title: String!, $subject: String!, $body: String!) {
  previewEmailTemplate(type: $type, recipientType: $recipientType, title: $title, subject: $subject, body: $body) {
    subject
    html
    availableFields {
      token
      name
      label
      kind
      group
      allowedIn
    }
  }
}

{
  "type": "string",
  "recipientType": "string",
  "title": "string",
  "subject": "string",
  "body": "string"
}

{
  "data": {
    "previewEmailTemplate": {
      "subject": "string",
      "html": "string",
      "availableFields": [
        {
          "token": "string",
          "name": "string",
          "label": "string",
          "kind": "string",
          "group": "string",
          "allowedIn": [
            "string"
          ]
        }
      ]
    }
  }
}