The workflow team has worked with the Azure team to create a product called Workflow Manager. Workflow Manager hosts the latest version of the Windows Workflow Foundation runtime and all the necessary services in an available and scalable way. It takes advantage of the Microsoft Azure Service Bus for performance and scalability, and when deployed, it runs exactly the same in an on-premises deployment as in the cloud, similar to Office 365. SharePoint is then connected and configured to hand off all workflow execution and related tasks to the Workflow Manager farm.
This change in the architecture required some changes to the two primary workflow authoring tools (SharePoint Designer 2013 and Visual Studio 2012) customers used to create custom workflows. However, the debugging techniques employed by developers in SharePoint 2007 and SharePoint 2010 still apply. The new architecture allows for a new option for workflows created using either SharePoint Designer 2013 or Visual Studio 2012 in that Fiddler can be used to monitor traffic between SharePoint and Workflow Manager.