Context Diagram

A system context diagram defines the boundary between a system and its environment, showing the entities that interact with it. It represents an overview of the main interactions between the system and the outside world. A context diagram focuses on the core relationships that the system maintains with external entities (other systems, organizational groups, external data stores, etc.). It depicts the system as a single central process, showing no details of its internal structure, surrounded by its interacting systems, parties, or processes. A context diagram is, in fact, a top-level (also known as "Level 0") data flow diagram.

A context diagram is a handy technique, especially in the early stages of a project, as it helps discover critical dependencies to better understand the situation and scope. It is also a valuable part of the documentation for a released system. Such a documentation overview assists in understanding the context of the system and serves as an information hub from which users can navigate to more detailed sections of the documentation.