VIESAC – Free VAT Validation for WooCommerce

Description

VIESAC is an automated VAT compliance and validation engine for WooCommerce. It provides real-time VAT number verification, local format validation, and an intelligent B2B Reverse-Charge & Place of Supply Decision Engine designed to keep international stores compliant with European and global tax rules.

VIESAC checks VAT numbers locally and connects directly to official registries:
* European Union (EU): Real-time checks via the European Commission’s EU VIES system for all 27 EU member states.
* United Kingdom (GB & XI): Great Britain VAT validation via the official HMRC VAT API; Northern Ireland (XI) validation via EU VIES.
* Switzerland (CH) & Liechtenstein (LI): Support for CHE format and Liechtenstein companies (Liechtenstein and Switzerland form a unified VAT territory; Liechtenstein VAT numbers follow the Swiss registry).
* Norway (NO): 9-digit MVA format & checksum verification; live VAT registration check via the Brønnøysund Register Centre (Enhetsregisteret).
* Serbia (RS): 9-digit PIB format & checksum verification; live company check via the Serbian Tax Administration VAT Register.
* Turkey (TR): 10-digit VKN algorithmic format verification; live taxpayer check via the Turkish Revenue Administration (GİB) e-Fatura registry.

Intelligent B2B Reverse-Charge & Place of Supply Engine

VIESAC automatically determines the correct tax treatment during checkout without complex configuration:
* Physical Goods vs. Digital/Virtual Services: Dynamically resolves the place of supply based on cart contents. Physical shipments evaluate the delivery/shipping destination; digital or purely virtual orders evaluate the customer’s billing country.
* Intra-EU B2B Reverse Charge: 0% VAT is applied automatically only when a buyer enters a valid VAT number from a different EU member state.
* Domestic Sales Protection: Domestic orders (destination matching the store’s base country) always retain standard local VAT, even if a valid local VAT number is provided.
* Unified Swiss-Liechtenstein Territory: Sales between Switzerland and Liechtenstein are recognized as domestic within the customs union, correctly preserving local tax.
* Cross-Border Exports: Cross-border sales to non-EU businesses (e.g. valid Serbian PIB, Turkish VKN, UK GB, Swiss CHE, or Norwegian MVA) qualify for 0% export VAT; unverified or invalid tax numbers retain standard tax.
* Instant Checkout Feedback: Field validation triggers immediately when a customer finishes typing and leaves the VAT input (blur / focusout), eliminating waiting pauses while preserving smart typing debounce.

1-Click Standard VAT Rate Setup

Merchants can import and configure the official standard VAT rate for their store base country in WooCommerce with a single click directly from the VIESAC settings page. Existing rates and custom reduced rates remain completely untouched.

Stored Proof & Audit Certificates

Every verified B2B transaction can be paired with permanent cryptographic proof and an official, downloadable PDF compliance certificate in order details for stress-free tax audits.

Features

• Automated Reverse-Charge Engine – Dynamic place of supply evaluation for goods vs. virtual services
• Real-time EU VIES Validation – Live verification for all 27 EU member states and Northern Ireland (XI)
• UK VAT checks via HMRC – Validate Great Britain (GB) VAT numbers through HMRC’s official API
• Serbian, Turkish & Norwegian Registries – Live verification of Serbian PIB (Tax Administration), Turkish VKN (GİB e-Fatura), and Norwegian MVA (Brønnøysund Register Centre)
• Unified CH-LI Territory – Seamless single-tax territory handling for Switzerland and Liechtenstein
• Instant Checkout Validation – Immediate verification on field blur/focusout with smart typing debounce
• 1-Click Standard VAT Rate – Easily configure the official standard rate for your store’s country
• Country-specific Format Checks – Instant client-side syntax and checksum validation without an API key
• Audit-Ready Certificates – Stored cryptographic proof and downloadable PDF certificates in WooCommerce orders
• Clear Usage Transparency – Clear distinction between monthly checks, hourly capacity, and stored proof quotas
• HPOS & Blocks Compatible – Fully compatible with WooCommerce Custom Order Tables and Checkout Blocks
• Multilingual Ready – Available in 28 languages, compatible with WPML, Polylang, and TranslatePress

VAT number validation by country

VIESAC includes country-specific VAT number format validation for every jurisdiction below. Live validation uses EU VIES for EU member states and Northern Ireland, HMRC for Great Britain, the Brønnøysund Register Centre for Norway, the Swiss UID register for Switzerland and Liechtenstein, the Serbian Tax Administration VAT Register for Serbia, and the Turkish Revenue Administration (GİB) e-Fatura taxpayer register for Turkey:

• Austria (AT) – Austrian VAT numbers
• Belgium (BE) – Belgian VAT numbers
• Bulgaria (BG) – Bulgarian VAT numbers
• Croatia (HR) – Croatian VAT numbers
• Cyprus (CY) – Cypriot VAT numbers
• Czechia (CZ) – Czech VAT numbers
• Denmark (DK) – Danish VAT numbers
• Estonia (EE) – Estonian VAT numbers
• Finland (FI) – Finnish VAT numbers
• France (FR) – French VAT numbers
• Germany (DE) – German VAT numbers
• Greece (EL/GR) – Greek VAT numbers
• Hungary (HU) – Hungarian VAT numbers
• Ireland (IE) – Irish VAT numbers
• Italy (IT) – Italian VAT numbers
• Latvia (LV) – Latvian VAT numbers
• Lithuania (LT) – Lithuanian VAT numbers
• Luxembourg (LU) – Luxembourg VAT numbers
• Malta (MT) – Maltese VAT numbers
• Netherlands (NL) – Dutch VAT numbers
• Poland (PL) – Polish VAT numbers
• Portugal (PT) – Portuguese VAT numbers
• Romania (RO) – Romanian VAT numbers
• Serbia (RS) – 9-digit PIB with checksum; live registration check through the Serbian Tax Administration with an API key
• Slovakia (SK) – Slovak VAT numbers
• Slovenia (SI) – Slovenian VAT numbers
• Spain (ES) – Spanish VAT numbers
• Sweden (SE) – Swedish VAT numbers
• Switzerland (CH/CHE) – CHE format; live UID register check; unified territory with Liechtenstein
• Turkey (TR) – 10-digit VKN with checksum; live GİB e-Fatura taxpayer register check with an API key
• Northern Ireland (XI) – Northern Irish VAT numbers through EU VIES (goods destination rules)
• Great Britain (GB) – UK VAT numbers through HMRC for England, Scotland, and Wales
• Norway (NO) – 9-digit MVA with checksum; live VAT registration check through the Brønnøysund Register Centre with an API key

Getting started

1. Install and activate the plugin.
2. Go to WooCommerce -> VIESAC.
3. Get your free API key from https://viesac.eu/app/api.
4. Enter the API key and save.

Languages

VIESAC is available in 28 languages: English, Norwegian Bokmål, German, French, Spanish, Italian, Polish, Dutch, Romanian, Greek, Czech, Swedish, Hungarian, Portuguese, Bulgarian, Danish, Finnish, Slovak, Croatian, Serbian (Cyrillic), Latvian, Estonian, Lithuanian, Slovenian, Russian, Turkish, Arabic, Ukrainian.

Multilingual compatibility

VIESAC uses standard WordPress gettext for its interface and VAT validation messages, so it works with WordPress language packs and the Gettext translation tools in WPML, Polylang, and TranslatePress.

Custom VAT field label and VAT field placeholder values are supported too:

• WPML: translate them in WPML -> String Translation after saving the VIESAC settings.
• Polylang: translate them in Languages -> String translations after saving the VIESAC settings.
• TranslatePress: translate them as regular strings in its translation editor after visiting checkout in the target language.

External services

This plugin connects to the VIESAC API to validate VAT numbers, retrieve account usage information, and optionally create audit records with certificate storage.

It sends data to https://viesac.eu only when a store administrator enters an API key and the plugin performs one of these actions:

• Live VAT validation via https://viesac.eu/api/v1/validate
• VAT audit creation via https://viesac.eu/api/v1/audits
• Account and usage lookup via https://viesac.eu/api/v1/account

Depending on the action, the plugin may send:

• VAT country code and VAT number
• Company name
• Company address
• Order number
• Order audit details in XML format for certificate generation

Service provider documentation:

• Privacy Policy: https://viesac.eu/privacy-policy
• Terms of Service: https://viesac.eu/terms-of-service