Over the last couple of years, workflow has evolved from its origins in image and document routing to become middleware technology for process automation and application integration. Workflow technology is now used in packaged applications and Internet-based electronic commerce process interactions, as well as for composing workflow process components in the world of business objects, processing of complex requests in a message broker environment, and coordinating interenterprise processes in a virtual enterprise. This article discusses the role of workflow standards in enabling interaction of independently developed workflow application components. It describes the evolution of these standards from programmatic interfaces for specialized workflow engines towards a workflow standards framework. It also describes the architectural principles of workflow-based applications on which the framework is based, and the adaptation of the framework to specific execution environments such as business object servers and message brokers.