Is Mermaid AI Playground free?

Yes, Mermaid AI Playground is completely free to use. No account, registration, or payment is required. All 22 diagram types and AI features are available at no cost.

Can I use Mermaid AI Playground with ChatGPT?

Yes! Mermaid AI Playground provides an MCP server at www.mermaid.help/api/mcp that works with ChatGPT Apps, Claude via MCP, Cursor, Windsurf, and other AI assistants that support the Model Context Protocol.

How does the AI diagram generation work?

The AI uses Google Gemini to convert your natural language description into valid Mermaid diagram code. It can also fix syntax errors and enhance existing diagrams for clarity.

Mermaid AI Playground — Free AI Diagram Generator & Editor

Mermaid AI Playground — MCP Server

Connect to generate, fix, enhance, and render any Mermaid diagram via the Model Context Protocol.

Quick Connect

MCP Endpoint

https://www.mermaid.help/api/mcp

Health Check

https://www.mermaid.help/api/mcp/health

No authentication required · Transport: Streamable HTTP · JSON-RPC 2.0

Use with ChatGPT Apps

Open ChatGPT → Explore GPTs → Create a GPT

Or open an existing GPT you want to enhance with diagrams.

Go to Configure → Actions → Create new action

Or add an MCP server under the "Tools" section if available.

Add the MCP endpoint URL

https://www.mermaid.help/api/mcp

Set Authentication to "None"

The server is open and requires no API keys.

Save and start using!

Ask your GPT to "generate a flowchart of the user login flow" and it will create and render diagrams.

Use with MCP Clients

Claude Desktop / Cursor / Windsurf

Add this to your MCP client config file:

{
  "mcpServers": {
    "mermaid-ai-playground": {
      "url": "https://www.mermaid.help/api/mcp"
    }
  }
}

cURL Test

curl -X POST https://www.mermaid.help/api/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-03-26","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}}}'

Available Tools

generate_mermaid_diagram

Generate Mermaid code from a natural-language prompt

Params: prompt, diagramType?, complexity?

fix_mermaid_diagram

Fix broken Mermaid syntax while preserving intent

Params: code, error?

enhance_mermaid_diagram

Improve structure and readability of existing diagrams

Params: code, goal?

render_mermaid_diagram

Render Mermaid code in an interactive accessible widget

Params: mermaidCode, title?, diagramType?

list_diagram_capabilities

List supported features and recommended workflow

Params: none

All 22 Supported Diagram Types

flowchartsequenceclassstateerganttjourneypiegitGraphtimelinemindmapquadrantChartrequirementsankeyblockpacketkanbanarchitecturexychartc4zenuml

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