A Gateway is a BPMN process modeling element used to control how sequence flows interact as they converge and diverge within a process. The term gateway is used to signify a mechanism by which something is either allowed or disallowed through.  A gateway is represented as a diamond.  Unlike activities, gateways do not represent work being done within a process flow.  They have no effect on operational measures such as cost, time, etc.

When discussing flow control, tokens that traverse the various flow paths are often discussed.  Gateways have the ability to consume or generate additional tokens. How these tokens are generated or consumed depends upon the type of gateway used, as identified by its internal marker. The types of internal markers that impact flow control are shown below.