See-Commerce is a completely modular solution for e-commerce. See-Commerce is entirely written in PHP and based on MySQL. It is simple for beginners, and very complete for advanced developers. See-Commerce supports value-added taxes, special price lists, discounts, transport fees, and a very comfortable Windows-based client from which you can browse all your e-commerce databases, orders, clients, etc. See-Commerce is currently only available in Italian.
XAO Commerce provides a set of objects and templates for building a modern eCommerce site. The functionality supported includes shopping cart, wallet, address book, category browsing, product database, searching, and administration tools. It also includes a complete working sample of an e-commerce site that can serve as a template for extensions. It is a full re-build of Symphero 3.1, which uses XAO Foundation Server and XAO Web Developer packages.
Arcavias is an e-commerce framework for Web shops, consisting of an e-commerce library, an administration interface, and different frontends. It's a modular stack which offers flexibility and speed. Unlike other Web shops, it's not a monolithic application. Instead, you have a choice between several user frontends, and you can adapt them to your needs or write one of your own.
Elastic Path is an enterprise e-commerce platform that provides an easy and cost-effective way to deliver a custom multi-store and multi-channel solution. It supports rich out-of-the-box features such as telco-style bundling, customer support functionality, product recommendations, dynamic content, merchandizing, promotion management, catalog management, and much more. It includes extensive documentation, full access to source code, and an active developer community.
doCommerce is an e-commerce platform, which uses PHP and MySQL. It is essentially osCommerce in Portuguese; the official releases of osCommerce are done for English, German, and Spanish. This package provides a Portuguese translation of osCommerce, and adds many of the contributions, modules, fixes, and patches that make it even more useful for the Portuguese online market.