Why evidence matters
When VAT treatment depends on the customer being VAT‑registered (for example, reverse charge or intra‑EU B2B supplies), retaining evidence that the VAT ID was valid at the relevant time supports your position in an audit.
Minimum record set
- Customer VAT identification number as used on the invoice (including country prefix).
- Date and time of validation (with timezone).
- Result status (valid/invalid/unavailable).
- Member state queried (derived from the prefix).
Recommended additions
- VIES request/consultation number (if displayed).
- Returned name and address fields (if provided).
- Screenshot/PDF export or system log record.
- Linkage to the underlying transaction (invoice/order/shipment reference).
When VIES is unavailable
- Save proof of the unavailability message and the timestamp.
- Re-run the check later and keep the later successful result.
- Document any alternative evidence used while VIES was unavailable.
Retention and access
Store verification evidence with the transaction documentation in a searchable format. Ensure the record can be reproduced (what was checked, when, and what the system returned).
Related pages
VAT verification overview | VAT formats by country | When to use VAT vs EORI vs LEI
