Medusa

Shopify powers tens of thousands of online retailers including General Electric, Amnesty International, CrossFit, Tesla Motors, Encyclopaedia Britannica, Foo Fighters, GitHub, and more. Our platform allows users to easily and quickly create their own online store without all the technical work involved in developing their own website, or the huge expense of having someone else build it. Shopify lets merchants manage all aspects of their shops: uploading products, changing the design, accepting credit card orders, and viewing their incoming orders and completed transactions.

WooCommerce is the most popular WordPress eCommerce plugin. And it's available for free. Packed full of features, perfectly integrated into your self-hosted WordPress website.

Magento Community Edition is perfect if you’re a developer who wants to build your own solution with flexible eCommerce technology. You can modify the core code and add a wide variety of features and functionality.

It is a true all-in-one ecommerce platform with the power to grow your business & help you sell more. It empowers you to rise above complexity – and ultimately focus on optimizing your business for growth.

PrestaShop is written in PHP, is highly customizable, supports all the major payment services, is translated in many languages and localized for many countries, and is fully responsive (both front- and back-office).