curl --request GET \
  --url https://api.steppay.kr/api/v1/customers \
  --header 'Secret-Token: <api-key>'

{
  "content": [
    {
      "id": 1,
      "code": "customer_AbCdEfGhI",
      "status": "NORMAL",
      "username": "test1@gmail.com",
      "name": "테스트 고객",
      "email": "test1@gmail.com",
      "phone": "01012345678",
      "orderCount": 0,
      "activeSubscriptionCount": 0,
      "paymentMethods": [],
      "marketingSms": false,
      "marketingEmail": false,
      "marketingKakao": false,
      "createdAt": "9999-01-01T00:00:00",
      "dormantAt": null,
      "customFields": {},
      "countryCode": "KR"
    },
    {
      "id": 1,
      "code": "customer_AbCdEfGhI",
      "status": "NORMAL",
      "username": "test2@gmail.com",
      "name": "테스트 고객2",
      "email": "test2@gmail.com",
      "phone": "01011231123",
      "orderCount": 1,
      "activeSubscriptionCount": 0,
      "paymentMethods": [
        {
          "id": 1,
          "paymentInfo": "XX카드 111111**********"
        }
      ],
      "marketingSms": false,
      "marketingEmail": false,
      "marketingKakao": false,
      "createdAt": "9999-01-01T00:00:00",
      "dormantAt": null,
      "customFields": {},
      "countryCode": "UNKNOWN"
    }
  ],
  "pageable": {
    "page": 0,
    "size": 20,
    "sortDir": "DESC",
    "sort": "createdAt",
    "pageSize": 20,
    "pageNumber": 0,
    "offset": 0,
    "paged": true,
    "unpaged": false
  },
  "last": true,
  "totalElements": 2,
  "totalPages": 1,
  "sort": {
    "unsorted": false,
    "sorted": true,
    "empty": false
  },
  "number": 0,
  "first": true,
  "numberOfElements": 20,
  "size": 20,
  "empty": false
}