Guides

Practical notes on validating EU VAT numbers with VIES, from someone who runs a VIES relay in production.

• VIES MS_MAX_CONCURRENT_REQ: what it means and how to handle it
  Why the EU VIES service returns MS_MAX_CONCURRENT_REQ, why retrying immediately makes it worse, and a retry strategy that works.
• How to validate an EU VAT number in Python
  Validate EU VAT numbers in Python against VIES: raw SOAP request with requests, parsing the answer, handling faults, and a simpler REST alternative.
• How to validate an EU VAT number in PHP
  Check EU VAT numbers against VIES from PHP with SoapClient: working code, fault handling, WooCommerce and Laravel tips, and a REST alternative.
• Why VIES returns no company name for German and Spanish VAT numbers
  VIES confirms German and Spanish VAT numbers but never returns the company name or address. Why, and how to handle it in your integration.

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