OpenFlow is a workflow engine developped by Icube and released as free software. It is based on an object oriented structure, it has a powerful exception handling system and it supports dynamic redesign. These features make OpenFlow much more flexible than other existing workflow engines. OpenFlow supports the open standards (XML/XML-RPC) and the web standards; it facilitates integration between heterogeneous systems thanks to simple access to most of relational databases. OpenFlow is activity based, multiplatform, web-based, WfMC inspired, built and integrated with the application server Zope, and it is completely free software.