How does billwerk validate the VAT ID of customers?


billwerk automatically checks in two ways whether the VAT ID specified by your customer is valid.

  1. A syntactic check
  2. A query at the VAT Information Exchange System (MIAS / VIES) of the European Commission

Syntactic check

The syntactic check evaluates the plausibility of the VAT ID entered on the order page. If the entered VAT ID does not consist of the two-digit country code as prefix and a maximum of twelve following aplhanumeric characters, the completion of the order is prevented until a syntactically correct or no VAT ID is stored.


VAT Information Exchange System query (VIES; European Commission)

billwerk automatically queries the validity of the VAT identification number stored in the VAT information exchange system VIES of the European Commission after a successful syntax check. Further information on VIES can be found here.

The check verifies if the VAT ID is currently valid. Queries to determine if the VAT ID fits the country of the customer or company name in billwerk are currently not included. 

The query is carried out automatically for the following events:

  • After customer registration
  • After changing the VAT ID
  • Recurring for VAT ID already tested:
    • 48 hours before the next regular payroll run (unless the last check was within the last 14 days)

The following statuses can have VAT IDs in billwerk:

  • Unconfirmed (After saving a new VAT ID, check is still in progress)
  • Confirmed on (Successful verification with date of verification)
  • Invalid on (according to the check, the VAT ID is invalid with the date of the last check)

The check is not performed for:

  • Swiss and UK VAT IDs
  • VAT IDs from the same country as you as a merchant

Impact of invalid VAT IDs for invoicing in billwerk

In the standard configuration, VAT IDs marked as invalid by VIES do not prevent the application of reverse-charge, if the other requirements for reverse-charge are fulfilled. 

This can be changed in "Settings > billing" via the checkbox "Apply reverse charge for contracts with invalid VAT ID". 


If you uncheck the option, a VAT ID number marked as invalid by VIES leads to new invoices in the contracts associated to the customer being created with VAT, even if the other requirements for reverse-charge are fulfilled. Also, old invoices can be corrected.

If the VAT ID is unconfirmed when an invoice is created, billwerk assumes that the VAT ID is valid and reverse charge is applied if the other requirements for it are fulfilled. 

Dealing with invalid VAT IDs 

If a VAT ID is marked as invalid, we disabled the recurring billing in all associated contracts and create a notification on our dashboard for you to follow up:


If the automatic billing has been deactivated due to an invalid VAT ID in a contract, this will happen again and again until:

a) the VAT ID is marked as valid in a subsequent validation

b) the VAT identification is removed from the customer

c) a valid VAT identification is registered 

You should therefore talk to your customer, explain the situation and work towards ensuring that the VAT ID is either valid or removed from the customer. 


After the correction, the system will not reactivate the automatic billing, this must be done manually.

The notification can be used as a reminder that there is an open issue. After resolving the issue with the customer you can acknowledge the notification to clean up your dashboard.


Was this article helpful?
2 out of 3 found this helpful