The workflow subsystem in Windows, starting with Vista. Introduced in the .NET Framework 3.0 programming interface (API), Windows Workflow Foundation (WWF) enables tasks to be automated. Workflows are described using .NET programming languages or the Extensible Application Markup Language (see XAML). WWF and WCF in Tandem WWF workflows are set up as activities that run sequentially or in parallel. A base set of activities are provided, and developers can create their own. In a Web services scenario, a WWF flow would be used to set up the logic, and the Windows Communication Foundation (WCF) messaging system would be used to send messages to applications. See Windows Communication Foundation.