Frequently Asked Questions

Below you will find the answers to the frequently asked questions. If your question isn't answered, you can contact us via the following e-mail address: .

The world is changing and Grant Thornton is developing with it. At the beginning of 2018, the Grant Thornton started the Opportunity identifer project (OPID). This means that we perform all kinds of analyzes based on our data for the benefit of our customers. With this Grant Thornton wants to connect with the new reality: the world of automation and digitization of processes and services.

Based on the developments of tax laws and regulations, we perform all kinds of data analyzes to proactively provide our clients with possible "tax opportunities". For more information you can contact us via

Both existing customers and non-customers of Grant Thornton can use our services on this website at all times as long as they are online.

No, you only require a version of Microsoft Excel. We recommend to make use of Microsoft Excel 2016 or a more recent version.

We recommend to validate up to 500 VAT identification numbers per validation request for optimal usage of the tool. It is however possible to validate even more numbers at once (as example 3.000 numbers).

The fee is a one time fee and there is an unlimited use of the tool after purchase.

Yes, upon receipt of the payment confirmation you will receive an e-mail including a link for downloading the tool.

No, unfortunately there is no demo version available. For a demonstration of the tool we would like to refer to the video on the website.

Yes, an user manual is available, which can be found on the following page:

It may be possible that the server of the VIES database is not responding. In that case it is unfortunately not possible to validate VAT numbers at that moment. Please also refer to the official VIES website to check the current status of the country servers:

The tool makes a connection with the official VIES database () and receives a response as result of the validation request. The results are returned and displayed in the tool.

Your data is stored securely confirm our 

To ensure secure payments, GTDienst uses Buckaroo's online payment solution. For more information about Buckaroo go to: .

Do you still have any questions?

If you have any further questions? don't hesitate to contact us at the following e-mail address or contact your contact person at Grant Thornton.