Mermaid lets you generate diagrams from a markdown-like markup language. Born out of need to simplify documentation, Mermaid has grown into a larger ecosystem with plugins for Confluence, Visual Studio Code and Jekyll to name a few. To see how it works, you can use the Live Editor on GitHub. Mermaid also has a convenient command line interface that lets you generate SVG, PNG and PDF files as output from definition files. We've been using Mermaid in many projects and we like the simplicity of describing graphs and flowcharts with markdown and checking in the definition files with the code repository.