Mermaid sample

“Mermaid Diagramming and charting tool JavaScript-based diagramming and charting tool.
It renders Markdown-inspired text definitions to create and modify diagrams dynamically.” - Mermaid-js

Diagrams

Sequence

Source code

sequenceDiagram
    participant Alice
    participant Bob
    Alice->>John: Hello John, how are you?
    loop Healthcheck
    John->>John: Fight against hypochondria
    end
    Note right of John: Rational thoughts <br/>prevail!
    John-->>Alice: Great!
    John->>Bob: How about you?
    Bob-->>John: Jolly good!

Graph

sequenceDiagram participant Alice participant Bob Alice->>John: Hello John, how are you? loop Healthcheck John->>John: Fight against hypochondria end Note right of John: Rational thoughts
prevail! John-->>Alice: Great! John->>Bob: How about you? Bob-->>John: Jolly good!