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Byte8 VAT Validator

A free, MIT-licensed Magento 2 module that validates B2B buyers' VAT numbers against the EU VIES REST API, UK HMRC's "Check a UK VAT number" v2.0 (OAuth 2.0), and the Swiss UID-Register — at customer registration and at checkout — and automatically moves validated customers into a configurable "Zero Tax" customer group so the right tax rules fire immediately.

Why this exists​

Magento's native VAT validation has three problems in 2026:

  1. It hits the deprecated VIES SOAP endpoint. Stores without ext-soap fail silently. The EC has signalled the SOAP endpoint will be retired.
  2. It has no UK coverage post-Brexit. GB VAT numbers can't be validated at all.
  3. It only fires at customer save, not at checkout. A logged-in B2B buyer who changes country at checkout gets the wrong tax.

This module is the modern replacement: REST-only (no ext-soap), EU + UK

  • CH coverage, and a non-blocking checkout path — every quote address save reads from a TTL-bounded result cache and queues an async revalidation if stale. Order placement is never blocked on VIES / HMRC / UID-CHE responsiveness.

What's new in v1.0​

  • Async checkout queue — byte8.vat.revalidate topic, DB-backed by default. See Async queue.
  • HMRC OAuth 2.0 — "Check a UK VAT number" v2.0 is application-restricted. Each merchant must register their own application. See HMRC.
  • Live "Verify VAT" buttons on Luma registration, account-edit, and checkout — shipped with the core module. See Luma storefront widgets.
  • Cache-aware REST /lookup for headless storefronts — see REST API.
  • Customer-facing notices on the storefront when a VAT can't be verified (non-blocking — order proceeds with full VAT applied).

Where to start​

If you've never installed the module, jump straight to the Quick start — it's a 5-minute Composer install + a couple of config flags.

If you're a German merchant who's reading this because you need a queryable validation log for §147 AO retention, start at Validation log overview.

If you're building a headless storefront, the REST API page and the VelaFront / Hyvä widgets are what you want.

What this module is NOT​

  • Not a tax-rule manager. It assigns customer groups; you still configure the tax classes + tax rules in standard Magento. See Customer Group Mapping for the worked example.
  • Not a German Steuernummer validator. The Steuernummer is a domestic Finanzamt identifier with no public lookup API — only syntactic validation per Bundesland is possible. Out of scope.
  • Not a billing / invoicing module. For invoice sync to Sage / Xero, see Byte8 Ledger.