Windows Workflow Foundation is a framework that enables users to create system or human workflows in their applications written for Windows Vista, Windows XP, and the Windows Server 2003 operating systems. It consists of a namespace, an in-process workflow engine, and designers for Visual Studio 2005. Windows Workflow Foundation can be used to solve simple scenarios, such as showing UI controls based on user input, or complex scenarios encountered by large enterprises, such as order processing and inventory control. Windows Workflow Foundation comes with a programming model, a rehostable and customisable workflow engine, and tools for quickly building workflow-enabled applications on Windows.

Scenarios that Windows Workflow Foundation addresses include:

• Enabling workflow within line-of-business applications.
• User-interface page flows.
• Document-centric workflows.
• Human workflows.
• Composite workflows for service-oriented applications.
• Business rule-driven workflows.
• Workflows for systems management.

Windows Workflow Foundation provides a consistent and familiar development experience with other .NET Framework 3.0 technologies, such as Windows Communication Foundation and Windows Presentation Foundation. The Windows Workflow Foundation API provides full support for Visual Basic .NET and C#, a specialized workflow compiler, debugging within a workflow, a graphical workflow designer, and developing your workflow completely in code or in markup. Windows Workflow Foundation also provides an extensible model and designer to build custom activities that encapsulate workflow functionality for end users or for reuse across multiple projects.