ddash: Mermaid Diagram Tool with URL-Based Storage and Claude Code Integration

What ddash Does

ddash is a Mermaid diagram tool that stores the entire diagram in the URL hash. This approach eliminates the need for a backend, user accounts, or external storage. You can share diagrams simply by sharing the URL, bookmark them, or paste them in pull requests.

Core Features

• Write Mermaid syntax on the left panel and see the rendered diagram on the right
• All diagram data is stored in the URL hash
• Share diagrams via URL, bookmark them, or include them in PRs
• Comes with a Claude Code skill for one-command installation
• Free with no signup required

Claude Code Integration

The tool ships with a SKILL.md file that enables Claude Code to generate and open diagrams directly during conversations. You can type commands like /diagram the auth flow and Claude Code will explore your code, build a Mermaid diagram, and open it in ddash.

Practical Use

This tool is particularly useful for developers who need to quickly create and share diagrams without managing storage or accounts. The URL-based approach makes diagrams instantly shareable and persistent as long as the URL is preserved.