---

name: mermaidjs-v11 description: Create diagrams and visualizations using Mermaid.js v11 syntax. Use when generating flowcharts, sequence diagrams, class diagrams, state diagrams, ER diagrams, Gantt charts, user journeys, timelines, architecture diagrams, or any of 24+ diagram types. Supports JavaScript API integration, CLI rendering to SVG/PNG/PDF, theming, configuration, and accessibility features. Essential for documentation, technical diagrams, project planning, system architecture, and visual communication.

Mermaid.js v11

Overview

Create text-based diagrams using Mermaid.js v11 declarative syntax. Convert code to SVG/PNG/PDF via CLI or render in browsers/markdown files.

Quick Start

Basic Diagram Structure:

{diagram-type}
  {diagram-content}

Common Diagram Types:

• flowchart - Process flows, decision trees
• sequenceDiagram - Actor interactions, API flows
• classDiagram - OOP structures, data models
• stateDiagram - State machines, workflows
• erDiagram - Database relationships
• gantt - Project timelines
• journey - User experience flows

See references/diagram-types.md for all 24+ types with syntax.

Creating Diagrams

Inline Markdown Code Blocks:

```mermaid
flowchart TD
    A[Start] --> B{Decision}
    B -->|Yes| C[Action]
    B -->|No| D[End]
```

Configuration via Frontmatter:

```mermaid
---
theme: dark
---
flowchart LR
    A --> B
```

Comments: Use %% prefix for single-line comments.

CLI Usage

Convert .mmd files to images:

# Installation
npm install -g @mermaid-js/mermaid-cli

# Basic conversion
mmdc -i diagram.mmd -o diagram.svg

# With theme and background
mmdc -i input.mmd -o output.png -t dark -b transparent

# Custom styling
mmdc -i diagram.mmd --cssFile style.css -o output.svg

See references/cli-usage.md for Docker, batch processing, and advanced workflows.

JavaScript Integration

HTML Embedding:

<pre class="mermaid">
  flowchart TD
    A[Client] --> B[Server]
</pre>
<script src="https://cdn.jsdelivr.net/npm/mermaid@latest/dist/mermaid.min.js"></script>
<script>mermaid.initialize({ startOnLoad: true });</script>

See references/integration.md for Node.js API and advanced integration patterns.

Configuration & Theming

Common Options:

• theme: "default", "dark", "forest", "neutral", "base"
• look: "classic", "handDrawn"
• fontFamily: Custom font specification
• securityLevel: "strict", "loose", "antiscript"

See references/configuration.md for complete config options, theming, and customization.

Practical Patterns

Load references/examples.md for:

• Architecture diagrams
• API documentation flows
• Database schemas
• Project timelines
• State machines
• User journey maps

Resources

• references/diagram-types.md - Syntax for all 24+ diagram types
• references/configuration.md - Config, theming, accessibility
• references/cli-usage.md - CLI commands and workflows
• references/integration.md - JavaScript API and embedding
• references/examples.md - Practical patterns and use cases