What is C4 Model?
The C4 model, created by Simon Brown, provides a hierarchical way to describe and communicate software architecture. It uses four levels of abstraction — System Context (level 1), Container (level 2), Component (level 3), and Code (level 4) — to let teams progressively zoom from a high-level view down to implementation details. It is map-like: each diagram has a clear purpose, audience, and level of detail, which avoids the common problem of trying to cram every concern into one box-and-line picture.
Also known as: c4, c4 diagrams.
Related terms
- System Context Diagram — C4 level 1 diagram showing a software system and its interactions with users and other external systems.
- Container Diagram — C4 level 2 diagram showing the deployable/executable units (applications, services, databases) that make up a software system.
- Component Diagram — C4 level 3 diagram decomposing a container into groups of related functionality (components) and their collaborations.
- Code Diagram — C4 level 4 diagram showing the implementation-level details (classes, interfaces, functions) of a component.