Satchmo
Satchmo's mission is to use Django to create an open source framework for creating unique and robust online stores. To provide maximum flexibility, Satchmo is licensed under the BSD license.
The plugin can be downloaded from http://code.google.com/p/satchmo-realex-payments/.
Shopify
With Shopify you can setup a gorgeous online store in minutes and sell just about anything. Join over 15,000 Shopify users and discover the most effective, simple way to start an online store.
http://www.shopify.com/Spreedly
Spreedly Subscriptions provides a total subscriber management solution for businesses that take recurring payments online. Plug in your Realex gateway, hook up to our super simple API, and you're all set to start handling recurring payments with ease.
Website: www.spreedly.com
Ubercart
Ubercart is an exciting open source e-commerce shopping cart that fully integrates your online store with Drupal, the leading open source content management system. This is a killer combination for anyone looking to build a community around a product, sell access to premium content, offer paid file downloads, and much much more! For the Realex Module please visit: www.drupal.org/project/uc_realex
VirtueMart
Virtue Mart is an Open Source E- Commerce solution to be used together with a Content Management System (CMS) called Joomla!. Joomla! and VirtueMart are written in PHP and can be used in typical PHP/MySQL environments"
www.virtuemart.net
Volusion
Volusion’s powerful ecommerce software is designed to help you open a successful online business. From Fortune 500 companies to small businesses, our hosted solution powers thousands of storefronts around the world. By providing you a comprehensive suite of tools, including built-in marketing and inventory features, you can easily build, manage, and grow your online business. Additionally, our “ecommerce think tank” of over 200 team members helps propel your success by offering Out of This World™ customer support and dozens of ecommerce services. Named a Top Place to Work and a National Customer Service Awards winner, our business is designed to create a thriving environment to better serve our clients
VP-ASP
WandSoft
More information is available on the WandSoft website www.wandsoft.com/esales
WordPress
WordPress shopping cart plugin gives you the ability to quickly and seamlessly integrate an online shop with a fully functional shopping cart interface into any Wordpress website. With the easy to use interface, you can set up your multiple products and categorize/organize them into multiple product categories. Add additional images to showcase your products so that users know what they are buying and add digital downloads to products if needed so that users can securely download paid files from your website
X-Authorize
X-Cart
X-Cart offers a do-it-yourself shopping cart solution that can easily be integrated into any PHP-compatible website.
The plugin can be downloaded from http://www.thexcartstore.com/free-realex-module-xcart.html and there is an installation tutorial available here http://vimeo.com/27771515
Zen Cart
