Turn Text Into Beautiful Diagrams
Write Mermaid syntax in the editor and watch your diagram render in real time. No drag-and-drop, no signup, no upload. AI cannot render diagrams — we use the Mermaid.js engine right in your browser.
What Is a Mermaid Diagram Generator?
A Mermaid diagram generator turns plain-text markup into professional vector diagrams. Instead of fighting with drawing tools or asking an AI to describe a picture, you type your diagram structure in Mermaid syntax — a Markdown-inspired language — and get a real, exportable SVG diagram in seconds. Mermaid is the most popular text-to-diagram tool on the web, used by GitHub, Notion, and countless developer documentation projects.
Mermaid.js (MIT license) parses your text and renders each element as SVG nodes using the browser's native SVG engine. The entire process happens client-side: your diagram code never leaves this page. There is no server, no API call, and no tracking.
Large language models cannot render diagrams. They can describe what a flowchart might look like, but they cannot produce a pixel-accurate, styled, and exportable SVG with real node positions, arrow paths, and layout algorithms. This tool generates the actual diagram, not a text description of one.
Flowcharts for processes and decision trees, sequence diagrams for API calls and user interactions, class diagrams for software architecture, ER diagrams for database design, state diagrams for system behavior, Gantt charts for project timelines, pie charts for proportions, and user journey maps for experience design.
Mermaid.js (1.4MB minified) loads once from a CDN, then every diagram renders in your browser tab. Your code, data, and diagrams stay entirely on your device. There is no upload, no cloud processing, no analytics on diagram content. Close the tab and nothing remains.
Frequently Asked Questions
Is this Mermaid diagram generator really free?
Yes, 100% free. No signup, no credit card, no daily limit, no watermark on exports. You can create unlimited diagrams of any type. Mermaid.js is open source (MIT) and the page has no ads or upsells.
What diagram types are supported?
8 types: Flowchart (graph TD/LR), Sequence Diagram, Class Diagram, State Diagram, Entity-Relationship (ER) Diagram, Gantt Chart, Pie Chart, and User Journey. Each type has its own syntax rules — use the type buttons to switch and the templates to see working examples.
Can I export my diagram as an image?
Yes. Click "Download SVG" to get a clean, scalable vector file you can open in Illustrator, Figma, or any vector editor. Click "Download PNG" for a high-resolution raster image suitable for slides, documents, and social media posts. Both are generated from the live preview.
Do you store my diagram code or data?
No. Your Mermaid code stays in your browser's memory for the session. Closing the tab or refreshing the page clears everything. There is no backend database, no cookies tracking diagram content, and no server-side processing at all.
Can I embed diagrams in GitHub or Notion?
Yes. GitHub and Notion both support native Mermaid rendering if you paste the code block with the `mermaid` language tag. Use this tool to prototype your diagram visually, then paste the code directly into your Markdown files. The SVG export is also ready for direct use in documentation sites.
Is Mermaid the same as PlantUML or Graphviz?
Mermaid is simpler and more human-readable than PlantUML and Graphviz (DOT). It is designed specifically for Markdown-friendly editing and integrates natively with GitHub, GitLab, and Notion. If you need more layout control or UML rigor, PlantUML may be better, but for 90% of diagramming needs Mermaid is the fastest path from text to diagram.
Can I use the exported diagrams commercially?
Yes. The diagrams you create are yours. Mermaid.js is MIT licensed, so the rendering engine imposes no restrictions. You can use exported diagrams in client presentations, internal documentation, published books, websites, or any commercial context without attribution.
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