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Flowchart
Free Online Mermaid Editor — Flowcharts, Sequence Diagrams & More
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What is Mermaid Editor?
Mermaid Editor is a free, browser-based tool for creating diagrams using Mermaid.js syntax. Write simple text, get professional diagrams. No signup, no install, no proprietary file formats — just open the editor and start building.
Used by developers, product managers, and technical writers to document systems, plan architectures, and communicate ideas visually. Your diagrams are version-control friendly and render identically every time.
Key Features
Real-Time Preview
See your diagram update instantly as you type. Pan, zoom, and inspect every detail in the live preview panel.
21+ Diagram Types
Flowcharts, sequence diagrams, ER diagrams, Gantt charts, mind maps, class diagrams, state diagrams, and more.
Export PNG, SVG & PDF
Download high-resolution exports for docs, presentations, and print. No watermark on free SVG exports.
Theme Presets
Choose from Tokyo Night, Dracula, Nord, GitHub, and more. Customize colors for every element in your diagram.
AI Diagram Generation
Describe what you want in plain English and let AI generate the Mermaid code. Edit and refine from there.
Intelligent Code Editor
Monaco-powered editor with syntax highlighting, autocomplete, error markers, and code folding for Mermaid syntax.
Supported Diagram Types
Create any diagram type supported by Mermaid.js — all free, all in one editor.
How It Works
1
Write Mermaid Code
Type or paste Mermaid syntax in the code editor. Use autocomplete and snippets to speed things up.
2
Preview & Style
Watch your diagram render in real time. Apply theme presets or fine-tune individual colors.
3
Export & Share
Download as PNG, SVG, or PDF. Share a link with your diagram code embedded in the URL.