With IBM Rational Host Access Transformation Services (HATS) you can create Web applications, including portlets, and rich client applications that provide an easy-to-use graphical user interface (GUI) for your 3270 applications running on IBM System z platforms and your 5250 applications running on IBM i platforms. These character-based 3270 and 5250 applications are referred to as host applications. You can also create Web services that provide standard programming interfaces to business logic and transactions contained within host applications.
With the WebFacing Tool as an installable feature of HATS, you can also create Web and portlet applications for your 5250 applications by converting, during development, data description specification (DDS) display file source members into a Web-based user interface. HATS and WebFacing applications can be combined into a single Web application using both types of transformations.