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EU VAT validation in Ruby / Rails

Validate EU VAT numbers in Ruby or Ruby on Rails using the standard Net::HTTP library. Zero gem dependencies — integrates cleanly with ActiveRecord models and Rails service objects.

Implementation steps

  1. 1

    Use Net::HTTP with use_ssl = true for the HTTPS request

  2. 2

    Set the Authorization header with your API key from ENV

  3. 3

    Parse the JSON response with Ruby's built-in JSON module

  4. 4

    Update your ActiveRecord model with the validation result and company name

Code example

Ruby

require 'net/http'
require 'json'

def validate_vat(country, vat_number)
  uri = URI("http://localhost:3000/api/v1/validate/#{country}/#{vat_number}")
  http = Net::HTTP.new(uri.host, uri.port)
  http.use_ssl = true

  request = Net::HTTP::Get.new(uri)
  request['Authorization'] = "Bearer #{ENV['TAXID_API_KEY']}"

  response = http.request(request)
  JSON.parse(response.body)
end

result = validate_vat('DE', 'DE123456789')

if result['valid']
  puts "Valid EU business: #{result['company_name']}"
elsif result['status'] == 'service_unavailable'
  # VIES is temporarily down — allow through and validate later
  puts 'VIES unavailable — retry later'
else
  puts 'Invalid VAT number'
end

cURL

curl "http://localhost:3000/api/v1/validate/DE/DE123456789" \
  -H "Authorization: Bearer $TAXID_API_KEY"

# {
#   "valid": true,
#   "status": "active",
#   "company_name": "Example GmbH",
#   "company_address": "Musterstraße 1, 10115 Berlin",
#   "cached": false
# }

API response

The TaxID API returns a consistent JSON response for every validation request:

200 OK (active)valid
{
  "valid": true,
  "status": "active",
  "country_code": "DE",
  "vat_number": "123456789",
  "company_name": "Example GmbH",
  "company_address": "Musterstraße 1, 10115 Berlin",
  "request_date": "2026-05-10T00:00:00.000Z",
  "cached": false,
  "request_id": "req_01j..."
}

Error handling

The API uses a consistent Stripe-style error format. Always handle service_unavailable separately — VIES has occasional downtime and you should not reject valid customers during outages.

active

VAT number is valid and the business is registered

invalid

VAT number format is wrong or not registered in VIES

service_unavailable

VIES or the national system is temporarily down — retry later

Evaluating EU VAT APIs? Compare TaxID vs Vatstack, Vatlayer, Avalara →

Ready to implement?

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