What is the function of a sequence diagram?

A sequence diagram serves a critical function in illustrating how objects within a system interact with one another over time. It details the flow of messages exchanged between these objects, presenting a clear visual representation of the order in which events occur and how they relate to one another. This is especially valuable in understanding complex processes, as it clarifies the sequence of actions and the interactions necessary to achieve a specific outcome.

By focusing on both the participants in the scenario (the objects) and the messages sent between them, sequence diagrams help teams analyze system behavior and design specifications effectively. They are essential tools in modeling dynamic behavior in software engineering and system design, allowing stakeholders to visualize how different parts of the system collaborate to fulfill use cases or functional requirements.