A portlet is a small, self-contained web application. Portlets are managed and displayed within a Portal. Typically, a portal page is displayed as a collection of non-overlapping portlet windows, with each portlet window displaying a different portlet. Hence a portlet (or collection of portlets) resembles a web-based application hosted in a portal.

Portlets can be configured to generated differing content and GateIn 3.2 has a number of default portlets that can be used in any portal built in the application.