Software Architect's Handbook

Sequence diagrams

Sequence diagrams model how components in a software system interact and communicate. They are one type of interaction diagram, which is a subset of behavior diagrams. Other interaction diagrams include the communication diagram, timing diagram, and interaction overview diagram.

Sequence diagrams describe a sequence of events from the software system. The following example shows the flow of logic within a system for price calculation:

Sequence diagrams are sometimes referred to as event diagrams or event scenarios. They can be used to see how components interact with each other and in what order they do so. Some examples ...