Sample MMD File Download

MMD is the file extension for Mermaid — a diagrams-as-code syntax that turns plain text into flowcharts, sequence diagrams, and entity-relationship diagrams. Instead of a GUI drag-and-drop tool, you write a short text description and a renderer draws the diagram, which means the diagram source can live in version control right alongside the code it describes.

GitHub and GitLab both render Mermaid blocks natively inside Markdown, and it's become a common output format for AI assistants asked to diagram a system — the model writes Mermaid syntax directly instead of generating an image.

Use the sample below to test a Mermaid parser, confirm a documentation pipeline renders .mmd files correctly, or check editor syntax-highlighting support for the format.