{
  "custom_fields": [
    {
      "klass": "topic",
      "name": "topic_field_2",
      "type": "json",
      "serializers": [
        "topic_view"
      ]
    },
    {
      "klass": "category",
      "name": "category_field_1",
      "type": "json",
      "serializers": [
        "basic_category"
      ]
    },
    {
      "klass": "group",
      "name": "group_field_1",
      "type": "string",
      "serializers": [
        "basic_group"
      ]
    }
  ]
}