Customer does not have a VAT number

No VAT Number

When a customer is not VAT registered, and no VAT is mentioned in the API content when posting an invoice, then Billit will overwrite an existing customer with VAT number.

A solution to fix this is to add an additional identifier, e.g.

company number
GLN number

{
 "OrderType": "Invoice",
 "OrderDirection": "Income",
 "OrderNumber": "QS-005457",
 "OrderDate": "2025-12-01",
 "ExpiryDate": "2025-12-30",
  "Customer": {
   "Name": "Politie XYZ",
   "PartyType": "Customer",
   "Identifiers": [
        {
        "IdentifierType": "CBE",
        "Identifier": "0793249999"  //This information is needed to make sure that a uniwue customer is created in Billit 
        }
    ],
   "Addresses": [
        {
        "AddressType": "InvoiceAddress",
        "Name": "Politie XYZ",
        "Street": "Oktrooiplein",
        "StreetNumber": "1a",
        "City": "Ghent",
        "Box": "301",
        "CountryCode": "BE"
        },
        {
        "AddressType": "DeliveryAddress", 
        "Name": "Politie XYZ",
        "Street": "Oktrooiplein",
        "StreetNumber": "1b",
        "City": "Ghent",
        "Zipcode" : "9001",
        "Box": "b",
        "CountryCode": "BE"
        }
   ]
   },
 "OrderLines": [
  {
   "Quantity": 1,
   "UnitPriceExcl": 0.1,
   "Description": "Box of cookies",
   "VATPercentage": 6
   },
 ]
}

Result is a unique customer in Billit: