What is Mermaid Validator?

Mermaid Validator is a developer tool designed for fast, dependency-free syntax validation of Mermaid diagrams. It identifies the diagram type and provides detailed error messages for invalid syntax.

How does Mermaid Validator help debug invalid diagrams?

It provides detailed parse-error messages that clearly indicate syntax issues and their precise locations within your Mermaid diagram text, making debugging straightforward.

Does it require `mermaid-cli` or external dependencies?

No, Mermaid Validator operates entirely without `mermaid-cli` or any external rendering processes. It utilizes JSDOM to provide a minimal, lightweight internal DOM environment.

Mermaid Validator

Name: Mermaid Validator
Author: LF112

byLF112

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Developer Tools

Productivity & Workflow

Security & Testing

Validates Mermaid diagram syntax and identifies diagram types without external dependencies.

This lightweight Model Context Protocol (MCP) server provides a focused solution for validating Mermaid diagram syntax. It exposes a single tool, `validate_mermaid`, which accepts any Mermaid diagram text and quickly determines its validity, returning either the detected diagram type or a detailed parse error message. Engineered with Bun and TypeScript, it operates efficiently by using JSDOM to create the minimal necessary DOM environment, eliminating the need for heavy external rendering processes like `mermaid-cli` and making it ideal for integration into various development workflows and AI agent systems.

Key Features

01Operates without dependency on `mermaid-cli` or any external rendering process

023 GitHub stars

03Single tool – `validate_mermaid` for comprehensive Mermaid syntax validation

04Supports all major Mermaid diagram types including flowchart, sequence, class, pie, and more

05Provides detailed parse-error messages for invalid diagrams

06Utilizes JSDOM for a minimal DOM environment, ensuring lightweight operation

Use Cases

01Automating syntax checks for Mermaid diagrams within development environments or CI/CD pipelines

02Integrating Mermaid syntax validation into AI agent workflows or chatbots

03Providing instant feedback on Mermaid diagram correctness for authors and developers