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:

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

Configuration via Frontmatter:

---
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">&#x3C;/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