List all custom fields

{
    "fieldOptions": [],
    "fieldRels": [],
    "fields": [
        {
            "title": "Another Test Title",
            "descript": null,
            "type": "",
            "isrequired": "0",
            "perstag": "ANOTHER_TEST_TITLE",
            "defval": null,
            "show_in_list": "0",
            "rows": "0",
            "cols": "0",
            "visible": "1",
            "service": "",
            "ordernum": "2",
            "cdate": "2018-11-15T21:43:38-06:00",
            "udate": "2018-11-15T21:43:38-06:00",
            "options": [],
            "relations": [],
            "links": {
                "options": "https://:account.api-us1.com/api/:version/fields/2/options",
                "relations": "https://:account.api-us1.com/api/:version/fields/2/relations"
            },
            "id": "2"
        },
        {
            "title": "Title",
            "descript": "Field  description",
            "type": "textarea",
            "isrequired": "1",
            "perstag": "PERSONALIZEDTAG",
            "defval": "Defaut Value",
            "show_in_list": "1",
            "rows": "2",
            "cols": "2",
            "visible": "1",
            "service": "google",
            "ordernum": "3",
            "cdate": "2018-11-15T21:42:40-06:00",
            "udate": "2018-11-15T21:49:52-06:00",
            "options": [],
            "relations": [],
            "links": {
                "options": "https://:account.api-us1.com/api/:version/fields/1/options",
                "relations": "https://:account.api-us1.com/api/:version/fields/1/relations"
            },
            "id": "1"
        }
    ],
    "meta": {
        "total": "2"
    }
}