A workflow is a work procedure where workflow steps represent the activities, users must follow in order to achieve the desired outcome. A workflow consists of a sequence of concatenated (connected) steps, where each step follows the precedent without delay or gap and ends just before the subsequent step may begin. This concept is related to non overlapping tasks of single resources. The Simple Workflow Service of Amazon (SWF) is a service that deals with the flow of work that builds climbing and flexible applications. It makes it easy to build applications that coordinate work across distributed components. It is one of the Application services of Amazon Web Services (AWS).