Mermaid Diagramming

• Domain-driven design documentation
• Object-oriented class structures
• Entity relationships and dependencies

Quick Start Examples

Class Diagram (Domain Model)

classDiagram
    Title -- Genre
    Title *-- Season
    Title *-- Review
    User --> Review : creates

    class Title {
        +string name
        +int releaseYear
        +play()
    }

    class Genre {
        +string name
        +getTopTitles()
    }

Sequence Diagram (API Flow)

sequenceDiagram
    participant User
    participant API
    participant Database

    User->>API: POST /login
    API->>Database: Query credentials
    Database-->>API: Return user data
    alt Valid credentials
        API-->>User: 200 OK + JWT token
    else Invalid credentials
        API-->>User: 401 Unauthorized
    end

Flowchart (User Journey)

flowchart TD
    Start([User visits site]) --> Auth{Authenticated?}
    Auth -->|No| Login[Show login page]
    Auth -->|Yes| Dashboard[Show dashboard]
    Login --> Creds[Enter credentials]
    Creds --> Validate{Valid?}
    Validate -->|Yes| Dashboard
    Validate -->|No| Error[Show error]
    Error --> Login

ERD (Database Schema)

erDiagram
    USER ||--o{ ORDER : places
    ORDER ||--|{ LINE_ITEM : contains
    PRODUCT ||--o{ LINE_ITEM : includes

    USER {
        int id PK
        string email UK
        string name
        datetime created_at
    }

    ORDER {
        int id PK
        int user_id FK
        decimal total
        datetime created_at
    }

Detailed References

For in-depth guidance on specific diagram types, see:

• references/class-diagrams.md - Domain modeling, relationships (association, composition, aggregation, inheritance), multiplicity, methods/properties
• references/sequence-diagrams.md - Actors, participants, messages (sync/async), activations, loops, alt/opt/par blocks, notes
• references/flowcharts.md - Node shapes, connections, decision logic, subgraphs, styling
• references/erd-diagrams.md - Entities, relationships, cardinality, keys, attributes
• references/c4-diagrams.md - System context, container, component diagrams, boundaries
• references/architecture-diagrams.md - Cloud services, infrastructure, CI/CD deployments
• references/advanced-features.md - Themes, styling, configuration, layout options

Best Practices

1. Start Simple - Begin with core entities/components, add details incrementally
2. Use Meaningful Names - Clear labels make diagrams self-documenting
3. Comment Extensively - Use %% comments to explain complex relationships
4. Keep Focused - One diagram per concept; split large diagrams into multiple focused views
5. Version Control - Store .mmd files alongside code for easy updates
6. Add Context - Include titles and notes to explain diagram purpose
7. Iterate - Refine diagrams as understanding evolves

Configuration and Theming

Configure diagrams using frontmatter:

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