Key Terminology

Activity: A single step of a flow, as represented by a node in the Flow Designer interface. For example, play a message or make an HTTP request. This is the element that is dragged and dropped by the user into a flow. The following are the key types of Activities available in Flow Designer:

Start Activities: These activities start a flow or path of a flow. They have zero inputs and one output. Start Activities include the Start Flow and the Event Handler activities. The Start Flow activity indicates the Trigger Event that causes a flow to be executed. The Event Handler activity allows you to build custom branches of a flow that are only executed if the indicated event is triggered at some point during the execution of the Main Flow. Start Activities have pentagon shape and shaded left-edge.
Actions: These activities are used in the middle of the flow and indicate a step that can only have one successful outcome. They have more than single inputs, two required outputs, and potentially some error handling outputs. Actions have square shape.
Enum-Gateways: These activities are used in the middle of the flow and indicate a step that can have multiple successful outcome paths. They have one or more inputs, two or more required outputs, and potentially some error handling outputs. Enum-Gateways have diamond shape.
Terminating Activities: These activities end a flow or flow path. They have one or more inputs and zero outputs. For example, the End Flow and Disconnect Contact activities are Terminating Activities that end either the flow or the contact depending on whether or not a contact is actively involved. Terminating Activities have circle shape and shaded right-edge. You must have at least one Terminating Activity in every flow to indicate that the flow ends eventually. You can have multiple terminating activities in a single flow to terminate different flow paths.

Event: An internal or external stimulus to the system which may cause a flow or flow path to be executed. These may be Kafka messages, external HTTP requests, user actions, etc. Flow Designer is an event-driven application that executes flows in response to events. If and when certain events are triggered, flows are automatically executed as configured.

Flow: A user-defined sequence of activities that are executed in response to an event.

Link: A link is the arrow that connects one activity to another. It indicates the direction of the flow and dependency between events. To delete a link and break the connection between two activities, click on the link to reveal the delete icon, and proceed to delete the line.

Port: A port is an unlinked output or input on an activity. It is a circle from which you can drag or connect a link. All ports must be linked, otherwise the flow is invalid.

Workflow Engine (WFE): A software application that manages process automation.