When you invoice a business customer outside your country — whether in the EU or beyond — you may be entitled to issue the invoice VAT-free (reverse charge). But this is not automatic. To legally omit VAT, you must verify that your customer is a registered taxable business in their country at the time of the invoice.
If you skip this step and a tax authority later audits you, the burden of proof falls on you. Without documented evidence that your customer was VAT-registered at the time of the transaction, the inspector can disallow the VAT exemption / reverse charge retroactively. That means you owe the VAT you didn't charge — out of your own pocket — plus interest and potential penalties.
There is a subtler problem that catches many businesses off guard: the evidence must reflect the status at the time of the invoice, not just the time of the audit. A customer who was registered when you invoiced them may have deregistered since. Without a timestamped certificate proving they were registered on the invoice date, you have a problem.
VATport solves this by generating a dated PDF certificate every time you validate a VAT number. You build an audit trail automatically, validation by validation, and you store it for the day you need it.
In short: checking VAT numbers on official websites is free. Proving you checked them, in a format that holds up to a tax inspector, is what VATport is for.
That said, every case is different.
VAT rules vary depending on whether you are selling goods or services, and who your customer is. Cross-border sales of services to EU businesses generally fall under the reverse charge mechanism, where the customer accounts for VAT in their country — but the rules differ for B2C sales, digital services, and certain regulated sectors. For goods sold to EU businesses, proof of transport or dispatch (CMR documents, freight invoices, delivery confirmations) is typically required alongside VAT registration evidence. For exports of goods to non-EU countries, customs clearance documentation is the primary proof of export, and VAT exemption conditions are governed by export regulations rather than VIES.
VATport helps you with one critical piece of this puzzle: verifying and documenting that your customer was a registered taxable entity at the time of the transaction. It does not replace the other documentation your specific transaction may require.
We strongly recommend consulting a qualified tax advisor or VAT specialist for your particular situation. The rules are complex, country-specific, and subject to change.