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VAT ID Validation (VIES)

VAT ID validation is essential for B2B compliance, reverse charge eligibility, and EU cross-border trade. docs101 integrates with VIES (VAT Information Exchange System) to validate European VAT identification numbers automatically — no manual action required.

What is VIES?​

VIES (VAT Information Exchange System) is the official EU system for validating European VAT identification numbers. It is operated by the European Commission and allows businesses to verify that a VAT ID is valid and active, retrieve company information from the VAT registry (name, address), determine reverse charge eligibility for cross-border B2B transactions, and maintain audit trails for compliance purposes.

Why VAT Validation Matters​

  • Compliance: Ensure customers have legitimate VAT registrations before applying reverse charge.
  • Risk Reduction: Avoid invoicing with invalid or fraudulent VAT IDs.
  • Reverse Charge: Reverse charge applies when a B2B customer has a valid VAT ID from a different EU country than the seller.
  • Audit Trail: Keep timestamped validation records for tax authorities.

Prerequisite: Your Own VAT Number​

To validate customer VAT IDs, your company must have a valid VAT number entered in Business Settings. The VIES system requires the requesting company to identify itself with a valid EU VAT ID.

When you enter or change your VAT number in Business Settings, docs101 validates it automatically via VIES — using the same smart caching and background retry logic described below. A status card on the Business Settings page shows the result.

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If your company VAT number is missing or invalid, customer VAT validation via VIES is not available. The VAT status card on the customer detail page will show a notice asking you to configure your VAT number in Business Settings first.

How Automatic Validation Works​

docs101 checks your customers' VAT IDs automatically at two key moments — you never need to trigger a check yourself.

When docs101 Checks​

TriggerWhat Happens
Opening the customer detail pagedocs101 checks whether a cached result exists and is still valid. If not, it starts a new VIES query in the background.
Selecting a customer on the invoice pageSame logic — if the cache has expired or no result exists, a background check is triggered automatically.

There is no manual "Validate" button. The check runs whenever you interact with a B2B customer that has a VAT ID.

Validation Statuses​

After a check is triggered, the VAT status card on the customer detail page shows one of four states:

StatusWhat It Means
Valid (green)The VAT ID is registered and active in the VIES database. Company name and address are displayed. The result is cached for 30 days.
Invalid (red)The VAT ID was not found or is not active. The result is cached for 24 hours, then automatically re-checked on the next page visit.
Pending (gray, animated)A VIES query is currently running in the background. The page updates automatically once a result arrives.
Retry (yellow)The VIES service is temporarily unavailable. docs101 retries automatically in the background with increasing delays until a response is received.
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You do not need to wait for a pending check to complete. You can continue working — the status card will update automatically once the result arrives.

Smart Caching​

docs101 uses differentiated caching to balance accuracy with performance. The caching strategy depends on the validation result:

Valid IDs — 30-Day Cache​

A confirmed valid VAT ID is cached for 30 days. During this period, opening the customer detail page or selecting the customer on an invoice will show the cached result instantly without querying VIES again. After 30 days, the next interaction triggers a fresh VIES check automatically.

Invalid IDs — 24-Hour Cache​

An invalid result is cached for only 24 hours. This ensures that a customer who corrects their VAT ID can be re-validated quickly. After 24 hours, the next page visit automatically triggers a new VIES query.

Service Errors — No Cache, Background Retry​

If the VIES service is unavailable (timeout, server error, maintenance), the result is not cached at all. Instead, docs101 enqueues a background retry job that runs with increasing delays (starting at 1 minute, up to 60 minutes between attempts, maximum 10 retries). Once VIES responds — whether the ID is valid or invalid — the result is cached normally.

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Background retries happen completely automatically. You do not need to check back or trigger anything manually. The status card will update from "Retry" to "Valid" or "Invalid" once a response is received.

VAT Check During Invoice Finalization​

When you finalize an invoice, the validation checklist includes a VAT ID check. The behavior depends on the current validation status:

Valid VAT ID — No Action Needed​

If the customer's VAT ID is valid, the checklist shows a green checkmark next to "VAT ID valid". You can finalize the invoice normally.

Invalid VAT ID — Confirmation Required​

If the customer's VAT ID is invalid, the finalize button is disabled until you explicitly acknowledge the situation. A confirmation checkbox appears:

I confirm that I want to finalize this invoice despite the invalid VAT ID.

Once you activate the checkbox, the finalize button becomes available. This confirmation is logged in the Audit Log as a VAT Override event for compliance documentation.

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Finalizing an invoice with an invalid VAT ID means you cannot apply reverse charge (0% VAT). Standard VAT rates will apply. Make sure this is intentional before confirming.

Pending Check — Proceed with Info Note​

If a VIES check is still running (status "Pending" or "Retry"), the checklist shows an informational note but does not block finalization. You can proceed — the validation result will be available shortly and will be stored with the customer record regardless.

Company VAT Missing — No Check Possible​

If your own company VAT number is not configured or invalid, customer VAT checks cannot run. The finalize checklist shows "VAT ID not verified" as a warning, but does not block finalization. No override confirmation is required because there is no "invalid" result — the check simply could not be performed. To enable VAT validation, configure a valid VAT number in Business Settings.

Understanding Validation Results​

Valid Status​

A valid VAT ID means the VAT ID exists in the EU VAT registry, the business is currently registered and active, the company information is accurate as of the last check, and reverse charge may apply if the customer is in a different EU country than the seller.

Invalid Status​

An invalid VAT ID may indicate a typo in the VAT ID format, a business that is not registered for VAT, a business that has been deregistered, a VAT ID that belongs to a different country than expected, or a business that has temporarily suspended its VAT registration.

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If a VAT ID is invalid, ask the customer to confirm their VAT ID and resubmit. If the customer cannot provide a valid ID, consider changing the customer type to B2C.

Viewing Validation Details​

Click Show details on the VAT status card to expand the detail section. This shows the full validation result including the VAT ID, registered company name, registered address (when available from the member state), the timestamp of the last check, and whether the result came from cache or a live query.

Last Checked Timestamp​

Each validation result includes a Last Checked timestamp showing when VIES was last queried. This helps with audit compliance (proving due diligence in customer validation), temporal context (understanding when the data was current), and planning (knowing when a cached result will expire and a fresh check will be triggered).

Reverse Charge Eligibility​

Reverse charge eligibility is determined based on the validation results:

Eligible for Reverse Charge​

This applies when the VAT ID is valid, the customer is a B2B customer, the customer is in a different EU country than the seller, and invoices show 0% VAT with a reverse charge statement.

Not Eligible​

This applies when the customer is B2C (no VAT ID), the VAT ID is invalid or pending validation, the customer is in the same country as the seller, and standard VAT applies on invoices.

What to Do If Validation Fails​

If the VAT ID Is Invalid​

  1. Verify with Customer: Ask the customer to confirm their VAT ID.
  2. Check Format: Ensure the correct country code prefix (DE, FR, IT, etc.).
  3. Confirm Status: Verify the business is active and registered for VAT.
  4. Wait for Re-Check: The invalid result expires after 24 hours. If the customer corrects their ID in the meantime, the next page visit will trigger a fresh check automatically.
  5. Alternative: If the customer has no valid VAT ID, change to B2C type.

If VIES Is Unavailable​

docs101 handles VIES downtime automatically. When the service is unreachable, a background retry job is created that attempts validation with increasing delays. You will see the "Retry" status on the VAT status card, and once a response is received, the card updates automatically. There is no need to retry manually.

If Company Information Does Not Match​

If VIES returns a different company name or address than what is in the customer record:

  1. Review Customer Data: Check what you entered matches what the customer provided.
  2. Compare Results: Look at the differences between your records and the VIES registry.
  3. Update Customer: Correct the customer record to match VIES data if appropriate.
  4. Document Changes: Note any corrections for the compliance audit trail.

Best Practices​

  • Trust the Automation: docs101 checks VAT IDs at the right moments — when you open a customer or select one for an invoice. No manual steps needed.
  • Review Invalid Results: When a VAT ID shows as invalid, investigate promptly. The 24-hour cache ensures a quick re-check after the customer corrects the issue.
  • Do Not Skip the Override: If an invalid VAT ID requires confirmation during invoice finalization, take it seriously. The override is logged for audit purposes.
  • Trust VIES: Rely on official VIES data over customer-provided information.
  • Compliance First: Do not apply reverse charge without a confirmed valid VAT ID.