System context diagram
A system context diagram is a high-level architecture diagram that shows a system as a single box at the center, surrounded by the people and external systems it interacts with.
In depth
System context diagrams are the top level of the C4 model (Context, Container, Component, Code) and the simplest useful architecture artifact. They make the system's boundary explicit — what's inside the box, what's outside, and which external integrations matter.
Variants include the basic C4 context (the system + actors + external systems), enterprise-context diagrams that nest multiple systems, and threat-modeling context diagrams that highlight trust boundaries.
OpenCharts supports C4-style context, container, and component diagrams via structured node types and templates, plus AI generation from a system description.
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Build a context diagramRelated terms
UML
UML (Unified Modeling Language) is a standardized family of diagrams used in software engineering to model systems, including class, sequence, activity, state, and use-case diagrams.
Data flow diagram
A data flow diagram (DFD) is a graphical representation of how data moves through a system, showing data sources, processes, data stores, and external entities.
Network diagram
A network diagram is a visual representation of computer or organizational networks, showing devices (nodes) and the connections (edges) between them.