Validating Tax IDs

Validating tax IDs is a crucial step in tax compliance in B2B sales. It is your business's responsibility to validate tax IDs, such as VAT or GST numbers, to apply reverse-charge if needed. This means that you will not charge tax on the transaction, but rather your customer that is buying your products or services will be responsible for paying the tax.

Fortunately, you can use Quaderno's Tax IDs API to validate your customers' tax IDs.

Validation is straightforward: make a GET request with the country and tax ID you want to validate.

curl --request GET \
  --url 'https://quadernoapp.com/api/tax_ids/validate?country=DE&tax_id=DE303954554'

You can obtain one of the following values in response:

• true if the tax ID is valid and represents an actual business.
• false if the tax ID is not valid.
• null if the external validation service is temporarily unavailable.

At the moment, Quaderno can verify these Tax IDs:

• EU VAT Numbers
• UK VAT numbers
• Australian Business Numbers
• New Zealand Business Numbers
• Quebec QST Registration Numbers
• Swiss UID Numbers

Check our blog’s articles about how the reverse-charge mechanism works and how to check if a company is VAT registered to learn more.