C4-PlantUML is an open-source project that provides a collection of PlantUML diagrams for the C4 architecture model, which is a simple and intuitive way to describe software architecture. These diagrams, created by Simon Brown, are used to depict the static and dynamic aspects of the architecture at different levels of detail. C4-PlantUML includes various building blocks, such as System Context, Container, Component and Deployment diagrams that follow the C4 model. It also provides a set of skinparam options that help customize the look and feel of the diagrams. The project is designed to be used in conjunction with PlantUML, a tool for creating UML diagrams using a simple text language. C4-PlantUML can be used to generate diagrams for various programming languages and platforms, including Java, .NET, Node.js, and AWS. Overall, the project aims to simplify the process of modeling and communicating software architecture using a standardized and consistent approach.