System Context Diagram

C4 level 1 diagram showing a software system and its interactions with users and other external systems.

What is System Context Diagram?

The System Context diagram is the entry point of a C4 model. It focuses on people and external systems that interact with the software system being described, deliberately omitting internal structure. Its goal is to establish scope and audience: who uses the system, which systems it depends on, and which systems depend on it.

Related terms

  • C4 Model — A lightweight architecture visualization approach that describes software systems across four levels: System Context, Container, Component, and Code.
  • Container Diagram — C4 level 2 diagram showing the deployable/executable units (applications, services, databases) that make up a software system.