Build the HomeTax bulk-issue upload sheet (전자세금계산서 일괄발급 엑셀) from up to 100 invoices, with business-number, byte-length, date and amount checks. Returns file_base64 (XLSX) to upload in HomeTax yourself

Example request

{
  "invoices": [
    {
      "type": "01",
      "date": "2026-10-12",
      "supplier": {
        "business_number": "280-30-01413",
        "name": "다고툴즈",
        "representative": "박지훈",
        "address": "경남 사천시 병둔2길 70",
        "business_type": "서비스",
        "business_item": "소프트웨어",
        "email": "hello@toolsthatdontupload.com"
      },
      "buyer": {
        "business_number": "220-81-62517",
        "name": "(주)예시상사",
        "representative": "김대표",
        "email": "buyer@example.com"
      },
      "items": [
        {
          "name": "웹사이트 제작",
          "quantity": 1,
          "unit_price": 1500000
        },
        {
          "name": "유지보수",
          "spec": "월",
          "quantity": 3,
          "unit_price": 100000,
          "day": 12
        }
      ],
      "purpose": "02"
    }
  ]
}