C4 model

[1][2] It is based on a structural decomposition (a hierarchical tree structure) of a system into containers and components and relies on existing modelling techniques such as Unified Modeling Language (UML) or entity–relationship diagrams (ERDs) for the more detailed decomposition of the architectural building blocks.

The launch of an official website under a Creative Commons license[3] and an article[4] published in 2018 popularised the emerging technique.

[1] The C4 model documents the architecture of a software system, by showing multiple points of view[5] that explain the decomposition of a system into containers and components, the relationship between these elements, and, where appropriate, the relation with its users.

Instead, the C4 model recommends using simple diagrams based on nested boxes in order to facilitate interactive collaborative drawing.

The technique also promotes good modelling practices such as providing a title and legend on every diagram, and clear unambiguous labelling in order to facilitate the understanding by the intended audience.