Context

The context of a system is the set of relationships, dependencies, and interactions between that system and its environment – the people, other systems, and external entities it exchanges information or influence with. Establishing context is how an architect delimits a system’s scope. Everything inside the boundary is the system’s own concern, and everything outside is a neighbor the system must specify an interface to.

arc42 distinguishes two complementary perspectives on context. The business context (sometimes called the logical context) describes the system’s external relationships in business terms, abstracting away technical or implementation detail and naming inputs and outputs by what they mean rather than how they’re carried. The technical context supplements this with the concrete detail – transmission channels, protocols, IP addresses, bus or hardware specifics – that the business context deliberately leaves out.

Both perspectives are commonly documented together as a context view, which renders the system as a single black box against the neighbors identified here.