Katamaze Documentation

VIES support for WHMCS

What is the VAT Information Exchange System (VIES)?

For all questions about VIES, please refer to the official FAQ page directly available on the website of European Union on ec.europa.eu.

The VIES-on-the-Web (VoW) service is monitored on a daily basis by a team of European Union in order to ensure its performance, availability and flow of traffic at all times. This team intervenes whenever there is a suspicious use of the system that violates the rules of use. When such behavior is observed, which is considered as unusual and potentially abusive to the system, they are obliged to block the IP that is sending requests. That said, please do not flood the VIES with unnecessary requests or the IP address of your WHMCS will be blocked and you will no longer be able to perform more checks. Please ensure that you always use the VIES under these rules:

  • 20k or less requests for VAT validation per day
  • Up to 5 validations to an unique VAT number per day
  • Avoid performing blank or null or white space or invalid (length, syntax) validations
  • Perform validations preferably until 10:00 AM CET and/or after 18:00 CET

As long as you perform validations within the lines of the disclaimer, you should have no issue at all. Also keep in mind that since there is no central VIES web database the reply from the corresponding national database would vary from 1 to 4 seconds and also that not all national databases provide additional informations about VAT (company name, ownership, address etc.).


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