Windows Workflow Foundation (WF) is a Microsoft technology for defining, executing, and managing workflows. This technology was first released in November 2006 as a part of .NET Framework 3.0. A workflow based program is like a traditional program that allow you to coordinate work and perform operations but have some important differences:

• Workflows are a declarative way of writing programs by linking together pre-defined activities rather than an imperative programming model of writing lines of code
• Workflows can handle long running work by persisting itself to a durable store, such as a database, when idle and loading again once there is work to be performed again
• An instance of a workflow can be modified dynamically while running in the case that new conditions arise that require the workflow to behave differently than the way it did when it was created
• Workflows provide a distinct separation of business rules and host application code making it easier to modify the business rules in the future
• Workflows support different types of systems with sequential workflows for sequential logic and state machine workflows for event-based logic
• Workflows usually have a visual counterpart to them that allows a flowchart-like description of the logic contained within it

Microsoft has indicated that WF is going to be a cornerstone of their future Service Oriented Architecture platform announced in October 2007 with the codename Oslo.