ISPadmin allows you to verify the validity of VAT numbers with the help of the VIES system. This kind of validation can be used in all EU localizations with the exception of the CZ one. In the CZ localization, the ARES system is used instead.

When you are adding/editing a client, you can click on the VIES button next to the VAT number field. When you do that, the system will check whether the VAT number in question is valid.

You can have the system show you all the clients for whom some kind of error occurred during the verification process. To do that, you have to click on the Continue button that can be found in the VIES row in the Other / Tools tab.