Pro pricing: TBD — stay tuned
Pro feature

VIES VAT number validation

Overview

VIES VAT number validation is a Pro feature that verifies customer-provided VAT numbers in real time during checkout. Valid VAT numbers trigger B2B classification, which excludes the order from your OSS threshold count.

This feature requires a Pro license. See the pricing page for details.

How it works

When a customer enters a VAT number at checkout:

  1. The plugin sends a validation request to the EU’s VIES (VAT Information Exchange System) service.
  2. VIES checks the number against the national VAT database of the relevant member state.
  3. If the number is valid, the checkout field displays a green checkmark and the order is classified as EU B2B.
  4. If the number is invalid, the field displays a red warning and the order is classified as EU B2C.

Validation happens inline as the customer types or tabs out of the VAT number field. There is no need to submit the form first.

B2B exemption

When a VAT number is validated successfully:

  • The order is classified as EU B2B rather than EU B2C.
  • The order does not count toward the EUR 10,000 threshold.
  • The customer’s VAT number and validation result are stored on the order for your records.

Depending on your WooCommerce tax configuration, you may also choose to apply a reverse charge (zero-rate VAT) to validated B2B orders. This is configured in your WooCommerce tax settings, not within the plugin itself.

VIES system status handling

The VIES service is maintained by the European Commission and is occasionally unavailable due to maintenance or national database outages. The plugin handles this gracefully:

Temporary unavailability

If the VIES service is temporarily unreachable (network timeout or HTTP error), the plugin:

  1. Retries the validation request once after a short delay.
  2. If the retry also fails, displays a neutral message to the customer: “VAT number could not be verified at this time.”
  3. Allows the order to proceed, classifying it as EU B2C by default.
  4. Flags the order for manual review in the WooCommerce > EU VAT OSS > Overview page.

Country-specific outages

Individual EU member states occasionally take their national VIES node offline for maintenance. When this happens, only VAT numbers from that specific country are affected. The plugin displays the affected country in the validation message so the customer understands the issue.

Validation log

Every validation attempt is logged with:

  • The VAT number checked (partially masked for privacy).
  • The validation result (valid, invalid, or unavailable).
  • The timestamp of the check.
  • The VIES response details.

The log is accessible at WooCommerce > EU VAT OSS > Settings > VIES Log and helps you review flagged orders and resolve any classification questions.

Checkout experience

The VAT number field appears at checkout based on your Display settings. When VIES validation is enabled:

  • The field shows a loading spinner during validation.
  • A green checkmark and company name (returned by VIES) confirm a valid number.
  • A red cross indicates an invalid number with an explanatory message.
  • Validation results are cached for the session to avoid repeated lookups if the customer navigates back to checkout.

Tips

  • Inform B2B customers — Add a note near the VAT field explaining that providing a valid VAT number may exempt them from destination-country VAT.
  • Review flagged orders — Check the overview page regularly for orders flagged due to VIES unavailability. You can manually validate these numbers later and reclassify the orders.
  • Monitor the VIES log — If you see frequent failures for a specific country, it may indicate an ongoing national database issue rather than a problem with your store.