Code Archaeology

Sep 7, 2026 · Fundamentals

Why C4 Starts with System Context Diagrams: A Step-by-Step Guide

This article explains why the C4 model begins with system context diagrams, detailing their purpose, key elements (people, software systems, relationships), notation conventions, and a step-by-step example of creating a context diagram for an online banking system integrating with core banking and email services.