What can be automated
Many billing, onboarding, and compliance workflows validate a customer’s VAT ID at account creation and again at invoicing. Automation usually centers on: input normalization, a VIES query, and structured result logging.
Input normalization rules
- Uppercase the country prefix.
- Remove spaces and punctuation.
- Keep the prefix + national identifier only (do not append extra characters).
- Reject obviously invalid inputs early (missing prefix, too short).
Handling rate limits and outages
- Use a retry policy with backoff for transient errors.
- Do not loop rapidly on failures; member state endpoints can be sensitive to bursts.
- Log ‘unavailable’ as a distinct technical state and schedule a later re-check.
Logging for traceability
- Persist the original input, normalized input, timestamp, result status, and any reference ID.
- Store returned name/address fields when available.
- Link the log to the customer record and the transaction record.
Interpreting outcomes
- Valid: proceed with VAT‑registered treatment where applicable.
- Invalid: request customer confirmation and treat as not VAT‑registered until validated.
- Unavailable: capture evidence and re-check later; use alternative proof if time‑critical.
Related pages
VAT verification overview | VAT formats by country | When to use VAT vs EORI vs LEI
