VAT Validation API

Validate EU VAT numbers against the official registry. Every check goes to VIES — the European Commission's VAT Information Exchange System, the same source national tax authorities use — and comes back as clean JSON: valid or not, plus the registered company name and address where the member state discloses them (Ireland does: IE6388047V → GOOGLE IRELAND LIMITED, 3rd Floor, Gordon House, Barrow Street; Germany validates but withholds identity — that's the German authority's policy, not a gap). Malformed numbers fail fast against the published per-country syntax rules WITHOUT burning a registry call, with the expected format and an example in the response. Accepts one combined string ('de 811-907-980' is cleaned up), or country + number separately; Greece's GR/EL quirk and Austria's ATU prefix are handled; GB numbers get a clear post-Brexit pointer to HMRC while Northern Ireland (XI) still works. A countries endpoint lists all 28 supported formats with LIVE per-member-state VIES availability, and registry answers are cached 15 minutes to absorb checkout bursts. B2B invoicing, reverse-charge logic, checkout tax exemption, supplier onboarding — the compliance check every EU-facing SaaS needs.