SilverStripe is a free and open source programming framework and content management system (CMS) for creating and maintaining websites. The CMS provides an intuitive web-based administration panel, allowing any person to maintain their website without knowledge of markup or programming languages.

SilverStripe contains a flexible MVC development framework known as Sapphire. Much like Ruby on Rails, but written in PHP5, it ensures developers are capable of extending and enhancing the functionality of the CMS and the website. SilverStripe provides developers with complete control of the generated markup; allowing for higher, semantic standards of XHTML. As a consequence, building websites using SilverStripe requires technical website development competence, and is thus aimed at providing efficiency and power to experienced website developers.

SilverStripe is released under the terms of the BSD Licence. Documentation is available for CMS users and website developers. A 450 page technical reference book on SilverStripe is available in German, with an English edition coming by August 2009. An online demonstration of the CMS is available as a video and as an interactive demo.