Runtime view

A runtime view is an architecture view that shows how a system’s building blocks – or their instances – cooperate at runtime to carry out a concrete scenario. Where the building block view shows a system’s static structure, the runtime view shows that structure in motion, the sequence of interactions between components as they collaborate to fulfil a specific use case, request, or event.

A runtime view is not expected to cover every possible path through a system. Because it documents a concrete scenario rather than the full space of behavior, a system typically needs several runtime views, each illustrating a different scenario chosen for its architectural significance – a critical business transaction, a failure mode, or an interaction pattern that recurs throughout the system.

Runtime views are commonly expressed as UML sequence diagrams or activity diagrams, though neither is mandatory. Any notation that conveys the ordering of interactions between building blocks will do. The runtime view is one of the standard viewpoints in architecture description frameworks such as arc42.