Active Merchant is a simple payment abstraction library used in and sponsored by Shopify. It is written by Tobias Luetke, Cody Fauser, and contributors. The aim of the project is to feel natural to Ruby users and to abstract as many parts as possible away from the user to offer a consistent interface across all supported gateways.
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Active Merchant

Active Merchant is an extraction from the e-commerce system Shopify. Shopify's requirements for a simple and unified API to access dozens of different payment gateways with very different internal APIs was the chief principle in designing the library.

Active Merchant has been in production use since June 2006 and is now used in most modern Ruby applications which deal with financial transactions.

It was developed for usage in Ruby on Rails web applications and integrates seamlessly as a plugin but it also works excellently as a stand alone library.

See {} if you want to learn more about using Active Merchant in your applications.


From Git

You can check out the latest source from git:

git clone git://

As a Rails plugin

ActiveMerchant includes an init.rb file. This means that Rails will automatically load ActiveMerchant on startup. Run the following command from the root directory of your Rails project to install ActiveMerchant as a Rails plugin:

script/plugin install git://

From RubyGems

Installation from RubyGems

gem install activemerchant

Alternatively, add the following to your Gemfile

gem 'activemerchant', :require => 'active_merchant'


This simple example demonstrates how a purchase can be made using a person's credit card details.

require 'rubygems'
require 'active_merchant'

# Use the TrustCommerce test servers
ActiveMerchant::Billing::Base.mode = :test

gateway =
            :login => 'TestMerchant',
            :password => 'password')

# ActiveMerchant accepts all amounts as Integer values in cents
amount = 1000  # $10.00

# The card verification value is also known as CVV2, CVC2, or CID
credit_card =
                :first_name         => 'Bob',
                :last_name          => 'Bobsen',
                :number             => '4242424242424242',
                :month              => '8',
                :year               => '2012',
                :verification_value => '123')

# Validating the card automatically detects the card type
if credit_card.valid?
  # Capture $10 from the credit card
  response = gateway.purchase(amount, credit_card)

  if response.success?
    puts "Successfully charged $#{sprintf("%.2f", amount / 100)} to the credit card #{credit_card.display_number}"
    raise StandardError, response.message

For more in-depth documentation and tutorials, see {} and the API documentation.

Supported Direct Payment Gateways

The ActiveMerchant Wiki contains a table of features supported by each gateway.

Supported Offsite Payment Gateways


The source code is hosted at GitHub, and can be fetched using:

git clone git://

Please see the ActiveMerchant Guide to Contributing for information on adding a new gateway to ActiveMerchant.

Please don't touch the CHANGELOG in your pull requests, we'll add the appropriate CHANGELOG entries at release time.

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