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

• Simple syntax verification
• Lookup via the VIES web service
• (Optional) ActiveModel/Rails3 integration
• Works standalone without ActiveModel
• 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

To verify the syntax of a vat number:

Valvat.new("DE345789003").valid?
=> true or false

To check if the given vat number exists via the VIES web service:

Valvat.new("DE345789003").exists?
=> true or false or nil

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

Visit http://ec.europa.eu/taxation_customs/vies/viesspec.do for more accurate information at what time the service for a specific country will be down.

It is also possible to bypass initializing a Valvat instance and check the syntax of a var number string directly with:

Valvat::Syntax.validate("DE345789003")
=> true or false

Or to lookup a vat number string directly via VIES web service:

Valvat::Lookup.validate("DE345789003")
=> true or false or nil

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
end

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}

If you want the vat number’s (ISO) country to match another country attribute, use the match_country option:

validates :vat_number, :valvat => {:match_country => :country}

where it is supposed that your model has a method named country which returns the country ISO code you want to match.

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?
    Valvat::Utils::EU_COUNTRIES.include?(country_code)
  end
end

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

Valvat::Utils.split("ATU345789003")
=> ["AT", "U345789003"]

or

Valvat.new("ATU345789003").to_a
=> ["AT", "U345789003"]

Both methods always return an array. If it can not detect the country or the given country is located outside of europe it returns [nil, nil]. Please note that this does not strictly return the ISO country code: for greek vat numbers this returns the ISO language code 'EL' instead of the ISO country code 'GR'.

To extract the ISO country code of a given vat number:

Valvat.new("EL7345789003").iso_country_code
=> "GR"

To extract the vat country code (first two chars in every european vat number):

Valvat.new("EL7345789003").vat_country_code
=> "EL"

To normalize a vat number:

Valvat::Utils.normalize("atu345789003")
=> "ATU345789003"

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

• VIES web service
• European vat number formats (german)
• European vat number formats on Wikipedia

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

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