Shopware is a scalable and customisable eCommerce platform. It is available in three editions: Community Edition - free and open source, Professional Edition and Enterprise Edition with a bunch of additional features included.
Its technology stack is based on PHP 7 and uses components from Symfony 3 and Zend Framework 2, including Doctrine 2 as an ORM. Templates are built on the Smarty engine.
Shopware is a stable and mature project. Comprehensive technical documentation and a free Udemy course shorten the learning time for developing custom plugins. In order to modify default behavior, Shopware provides a set of events available to hook and the dependency injection.
As a developer you can start selling your plugins in the official Shopware Store.
Shopware is suitable for mainly small businesses. It can be set up relatively quickly and it's the most optimized one for the EU market.
The new version 6 is a completely new product with no backwards compatibility. Therefore we don't recommend Shopware 5.x anymore for the new projects, although the version 5 is still going to be maintained until 2024.