Solving a CAPTCHA

There are several countries that have online validation of VAT numbers but have them protected by a CAPTCHA.

In the case that a CAPTCHA is required to be solved prior to validating a VAT number, there are a number of methods to do this:

  • Taxamo Checkout form - Taxamo will present the CAPTCHA image to the customer on the Checkout form and pass the information to the tax authority.
  • Taxamo API (note: the private API token is required for these operations) - The Taxamo API can provide a Base64 image of the CAPTCHA for presentation to the customer. The solution is returned to Taxamo based on input from the customer and Taxamo validates this with the tax authority.

Note: For some integrations, it may not suit the merchant to present a CAPTCHA on the checkout. Should this be the case there may be other options on how to manage CAPTCHA. Please discuss with us whether other options are available.


Taxamo will indicate whether the buyer_tax_number_valid is true or false. If the buyer tax number has been provided and was validated successfully, the response will be true.


If there is an error returned from the third-party B2B validation service this will be returned in the response as a warning, for example:

[{"type": "b2b-error", "message": "...any other error..."}], [" service is not available"]

When the number cannot be validated the buyer_tax_number_valid will be returned as null.

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