Get all custom fields

Example response

{
  "items": [
    {
      "fieldId": 1,
      "name": "Text Field 1",
      "type": "Text",
      "mandatory": true,
      "maxLength": 50,
      "multiLine": true
    },
    {
      "fieldId": 2,
      "name": "List Field 2",
      "type": "List",
      "mandatory": true,
      "multiSelect": true,
      "values": [
        "Value 1",
        "Value 2",
        "Value 3"
      ]
    },
    {
      "fieldId": 3,
      "name": "Date Field 3",
      "type": "Date",
      "mandatory": true
    }
  ]
}