An open-source CMS (content management system) is software for creating and managing website content whose source code is publicly available. Anyone can view it, modify it and extend it, and it is usually free to download and use. Well-known examples are WordPress, Drupal and Joomla, and for online stores PrestaShop.

The main advantages are no licence fees, a large community, a wide choice of modules and themes, the flexibility to adapt the system to specific needs and independence from a single vendor: you own your data and can move to another hosting provider or developer at any time. The price for this freedom is responsibility. You have to take care of updates, security and hosting, the quality of extensions varies and support usually comes from the community or from paid partners.

For an online store, an open-source platform gives full control over design, functions and data. Costs go into development, hosting and maintenance instead of licences. When choosing one, look for a well-maintained project with an active community, regular security updates and good documentation.