This documentation is for Taxamo v1. If your account is with Taxamo v2 use the documentation at integrate.taxamo.com/doc.
If you are uncertain of your version please contact support@taxamo.com for assistance.

Why aren't VAT numbers validated for domestic transactions?

As all domestic transactions are considered taxable there is no benefit to validating VAT numbers for domestic transactions.

If the number is valid, we will charge VAT, and if it’s not registered we will charge VAT as well.