Validates european vat numbers. Standalone or as a ActiveModel validator.


  • Simple syntax verification
  • Lookup via the VIES web service
  • Works standalone without any gem dependencies
  • (Optional) ActiveModel/Rails3 integration
  • I18n locales for country specific error messages

valvat is tested and works with ruby 1.8.7/1.9.2 and ActiveModel 3.0.


gem install valvat

Basic Usage

To verify the syntax of a vat number:

=> true or false

To check if the given vat number exists:

=> true or false or nil

Keep in mind that the VIES webservice might be offline at some time for some countries. If this happens Valvat::Lookup.validate returns nil.

Visit for more accurate information at what time the service for a specific country will be down.

ActiveModel/Rails3 Usage

When the valvat gem is required and ActiveModel is already loaded, everything will work fine out of the box. If your load order differs just add

require 'valvat/active_model'

after ActiveModel has been loaded.

To validate the attribute vat_number add this to your model:

class MyModel < ActiveRecord::Base
  validates :vat_number, :valvat => true

To additionally perform a lookup via VIES:

validates :vat_number, :valvat => {:lookup => true}

By default this will validate to true if the VIES web service is down. To fail in this case simply add the :fail_if_down option:

validates :vat_number, :valvat => {:lookup => :fail_if_down}

By default blank vat numbers validate to false. To change this add the :allow_blank option:

validates :vat_number, :valvat => {:allow_blank => true}

To allow vat numbers from outside of europe, add something like this to your model (country_code should return a upcase iso country code):

class MyModel < ActiveRecord::Base validates :vat_number, :valvat => true, :if => :eu?

def eu?



To split a vat number into the ISO country code and the remaining chars:

=> ["AT", "U345789003"]

split always returns an array. If it can not detect the country or the given country is located outside of europe it returns [nil, nil].

To normalize a vat number:

=> "ATU345789003"

This basically just removes trailing spaces and ensures all chars are upcase.



Copyright (c) 2011 Yolk Sebastian Munz & Julia Soergel GbR

Beyond that, the implementation is licensed under the MIT License.