Mermaid Diagram Generator n Editor

Features

Everything you need to create, edit, and export beautiful diagrams — directly in your browser, for free.

Editor & Preview

Real-Time Preview

Your diagram renders instantly as you type Mermaid code. No need to click a button — see changes live with zero delay.

↔️

Resizable Split Panel

Drag the splitter between the code editor and preview to allocate exactly the screen space you need for each.

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Built-In Examples

Load ready-made diagrams — flowchart, sequence, class, Gantt, ER, pie, journey, state, and more — with a single click.

Fullscreen Mode

Expand the canvas or the whole app to fullscreen to focus on your diagram without distractions.

Visual Canvas Editor

🖱️

Drag-and-Drop Nodes

Add rectangles, rounded boxes, diamonds, and circles by clicking shape tools, then drag them anywhere on the canvas.

➡️

Visual Arrow Connections

Hover any node to reveal blue anchor dots. Drag from a dot to another node to draw an arrow. Supports forward, bidirectional, and plain connections.

✏️

Inline Label Editing

Double-click any node or arrow to edit its label directly on the canvas — no dialog boxes needed.

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Color & Font Controls

Customise fill, stroke, and text colors from a 20-swatch palette. Change font family, size, bold, italic, and underline per element.

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Bidirectional Conversion

Convert your Mermaid code to an editable canvas with one click, or export your canvas drawing back to clean Mermaid syntax instantly.

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Auto-Save

Your work is automatically saved to the browser session. Ctrl+S saves to persistent local storage so nothing is lost on refresh.

Diagram Types

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Flowchart

The classic graph TD/LR diagram for decision trees, process flows, and system architectures.

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Sequence Diagram

Model interactions between actors and systems with messages, loops, and activation boxes.

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Class Diagram

Design object-oriented class structures with attributes, methods, and relationships — UML-ready.

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Gantt Chart

Plan projects with tasks, sections, and date-based timelines rendered as horizontal Gantt bars.

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Entity Relationship (ER)

Model database schemas and data relationships with cardinality annotations.

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Pie, State, Journey & More

Also supports pie charts, state diagrams, user journey maps, quadrant charts, and Gitgraph diagrams.

File Management & Export

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File Manager

Save multiple named diagrams in your browser. Create, rename, open, and delete files — no account or server required.

🖼️

Export PNG / JPEG

Download your diagram as a high-quality raster image — perfect for presentations, documents, and reports.

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Export SVG

Download a lossless vector SVG file that scales to any size — ideal for technical documentation and print.

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100% Client-Side

No data leaves your browser. Your diagrams are never sent to any server — complete privacy by design.