These systems apply templates on-demand. HTML may be generated when a user visits the page or pulled from a cache.

Most open source WCMSs have the capability to support add-ons, which provide extended capabilities including forums, blog, wiki, Web stores, photo galleries, contact management, etc. These are often called modules, nodes, widgets, add-ons, or extensions. Add-ons may be based on an open-source or paid license model.

Different WCMSs have significantly different feature sets and target audiences. Longtime WCMS research and evaluation firm Real Story Group (formerly CMS Watch) identifies five different tiers of WCMS vendors and open source projects.^[7]