A relying party (RP) application consumes the tokens issued by a Security Token Service (STS) and extracts the claims from tokens to use them for identity related tasks. The following diagram shows how WIF processes requests for an RP.

WIF helps you to build two types of RP application: ASP.NET Web applications, and Windows Communication Foundation (WCF) Web services. For more information, see How to: Build an ASP.NET Relying Party Application and How to: Build a WCF Relying Party Application.