curl --request POST \
  --url https://api.heffl.com/api/v1/invoices \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "clientId": "<string>",
  "date": "2023-11-07T05:31:56Z",
  "dueDate": "2023-11-07T05:31:56Z",
  "lineItems": [
    {
      "name": "<string>",
      "productId": "<string>",
      "quantity": 0,
      "price": 0,
      "description": "<string>",
      "taxRateId": "<string>",
      "discount": 0,
      "discountType": "fixed",
      "buyPrice": 0
    }
  ],
  "isInclusiveTax": false,
  "status": "DRAFT",
  "contactId": "<string>",
  "subject": "<string>",
  "notes": "<string>",
  "salesPersonId": "<string>",
  "templateId": "<string>",
  "tags": []
}
'

{
  "id": "<string>",
  "number": "<string>",
  "date": "2023-11-07T05:31:56Z",
  "dueDate": "2023-11-07T05:31:56Z",
  "status": "<string>",
  "currency": "<string>",
  "isInclusiveTax": true,
  "subTotal": 123,
  "taxTotal": 123,
  "discountTotal": 123,
  "total": 123,
  "pendingTotal": 123,
  "paidTotal": 123,
  "lineItems": [
    {
      "name": "<string>",
      "quantity": 123,
      "price": 123,
      "tax": 123,
      "discount": 123,
      "discountType": "fixed",
      "buyPrice": 123,
      "viewType": "LINE_ITEM",
      "amount": 123,
      "taxAmount": 123,
      "discountAmount": 123,
      "description": "<string>",
      "productId": 123
    }
  ],
  "createdAt": "2023-11-07T05:31:56Z",
  "clientId": "<string>",
  "contactId": "<string>",
  "subject": "<string>",
  "notes": "<string>",
  "salesPersonId": 123,
  "customFields": {}
}