C4Sharp (`C4S`) is a .net library for building diagram as code, based on C4 Model. With C4Sharp, developers can create, share, and consume C4 Model diagrams as code such as Context, Container, Component, and Deployment diagrams. The library generates multiple diagram types, including PNG, SVG, puml, and Mermaid. C4Sharp can be installed through Nuget Packages, and it requires .NET 5.0+ and Java to run. Additionally, C4Sharp provides a CLI for compiling C4S projects. C4 Model is an easy-to-learn, developer-friendly approach to software architecture diagramming that can assist with communication, onboarding of new staff, architecture reviews, risk identification, threat modeling, and more. There are many tools in this space, including Diagrams, Structurizr DSL, AsciiDoctor Diagram, and more.