Sling is different from many other Web application frameworks in the sense that it truly focuses on the web aspect of the "web application" development and through its development paradigm suggests an intuitive RESTful development of a true web application. Other frameworks focus more on the application development and therefore are ideal extensions to Sling.
The Sling project was started on August 27, 2007, when Day Software proposed to donate the source base of its internal web framework powering the Day Communiqué WCM to the Apache Software Foundation. The project was accepted to the Apache Incubator with Apache Jackrabbit being the sponsoring project. On June 18, 2009  the project graduated as Apache top-level project.
- Content resolution that maps a request URL to a content node in the content repository
- Servlet resolution that maps a content node and a request method to a Servlet handling the request
- Default servlets supporting WebDAV, content creation from web forms and JSON representation
- OSGi-based extensibility through Apache Felix – the Felix Web Console was originally developed by the Apache Sling project
- "Archived copy". Archived from the original on 2008-08-01. Retrieved 2008-08-27.CS1 maint: Archived copy as title (link)
- "Archived copy". Archived from the original on 2008-09-17. Retrieved 2008-08-28.CS1 maint: Archived copy as title (link)