Mermaid is an open-source library that renders diagrams from simple text definitions. It's used in GitHub, GitLab, Notion, and other documentation tools.

What diagram types are supported?

12 types: flowcharts, sequence diagrams, class diagrams, state diagrams, ER diagrams, Gantt charts, pie charts, mind maps, git graphs, user journeys, quadrant charts, and timelines.

How does AI diagram generation work?

Click 'AI Generate', describe your diagram in plain English (e.g. 'a login flow with OAuth'), and AI creates the Mermaid code for you. You can also pick a specific diagram type.

Can AI fix my broken Mermaid code?

Yes. When your code has a syntax error, an 'AI Fix' button appears. Click it and AI will repair the syntax automatically.

Can I share my diagrams?

Yes. Click the share button to copy a URL that encodes your diagram. Anyone with the link sees exactly what you see.

Can I export my diagrams?

Yes, export as SVG (vector, perfect for documents) or PNG (2x resolution, great for presentations).

Diagram rendering is 100% client-side. AI features send your code to our server for processing, but nothing is stored permanently.

Can I use Mermaid syntax from GitHub?

Yes, our editor uses the same Mermaid library used by GitHub, GitLab, and other platforms. Your syntax is fully compatible.

Mermaid Editor: AI Generation & Templates

Free Online Mermaid Diagram Editor with AI — Generate Flowcharts, Sequence Diagrams & More

Create professional diagrams instantly with our free Mermaid editor. Describe what you need in plain English and let AI generate the diagram for you, or write Mermaid syntax directly with live preview. Supports 12 diagram types including flowcharts, sequence diagrams, class diagrams, ER diagrams, Gantt charts, mind maps, git graphs, timelines, and more. Export to SVG or PNG, share via URL, zoom and pan your preview, switch themes, and undo/redo freely — all in your browser.

Key Features

AI diagram generation — describe what you need in plain English and get working Mermaid code
AI syntax fix — one-click repair when your Mermaid code has errors
Live preview as you type with automatic rendering
12 diagram templates: Flowchart, Sequence, Class, State, ER, Gantt, Pie, Mind Map, Git Graph, User Journey, Quadrant Chart, and Timeline
5 Mermaid themes: Default, Dark, Forest, Neutral, and Base
Zoom, pan, and fullscreen preview for detailed inspection
Share diagrams via URL — anyone with the link sees your diagram
Undo/redo with keyboard shortcuts (Ctrl+Z / Ctrl+Shift+Z)
Line numbers, tab indentation, and auto-indent
Resizable editor and preview panels
Export diagrams as SVG (vector) or PNG (2x resolution)
Copy Mermaid code or SVG output to clipboard
Diagram rendering is 100% client-side — your code stays private

SimplyUtils vs Other Mermaid Editors

Feature

SimplyUtils

mermaid.live

draw.io

Lucidchart

Free to Use

✓

Freemium

AI Diagram Generation

✓

✗

Paid

AI Syntax Fix

✓

✗

Live Preview

✓

✗

Starter Templates

12 types

3 types

✓

Theme Options

5 themes

4 themes

Limited

✓

Zoom & Pan

✓

✗

✓

Share via URL

✓

✗

Paid

SVG Export

✓

Paid

PNG Export

✓

Paid

No Sign-Up

✓

✗

Undo/Redo

✓

✗

✓

Fullscreen Preview

✓

✗

✓

Why Choose SimplyUtils over mermaid.live

While mermaid.live is the official Mermaid editor, SimplyUtils goes further with AI-powered diagram generation and syntax fixing. Describe your diagram in plain English and get working code instantly. We also offer 12 built-in templates (vs 3), zoom and pan controls, fullscreen preview, undo/redo, and 5 theme options. All rendering happens client-side with no data sent to any server.

Why Choose SimplyUtils over draw.io

draw.io (diagrams.net) is a powerful drag-and-drop diagramming tool, but it can be slow for quick diagrams and doesn't support text-based Mermaid syntax. SimplyUtils lets you create and iterate on diagrams much faster with code, and our AI generation means you don't even need to know the syntax — just describe what you want. Share diagrams via URL without creating accounts or saving files.

Why Choose SimplyUtils over Lucidchart

Lucidchart is a premium diagramming tool that requires sign-up and locks AI features and exports behind a paywall. SimplyUtils gives you free AI diagram generation, free SVG and PNG exports, and shareable URLs — no account required. For developers who prefer code-based diagrams, our Mermaid editor is faster and more lightweight.

What is Mermaid?

Mermaid is an open-source JavaScript library that renders diagrams from text-based definitions. It's widely used in documentation platforms like GitHub, GitLab, Notion, and Obsidian. Instead of dragging and dropping shapes, you write simple text like A --> B and Mermaid turns it into a visual diagram.

Supported Diagram Types

Flowcharts — process flows, decision trees, and workflows
Sequence diagrams — API calls, message flows, and system interactions
Class diagrams — object-oriented design and UML
State diagrams — state machines and lifecycle flows
ER diagrams — database schemas and relationships
Gantt charts — project timelines and scheduling
Pie charts — data distribution and percentages
Mind maps — brainstorming and idea organization
Git graphs — branch, merge, and commit visualization
User journeys — user experience and workflow mapping
Quadrant charts — priority matrices and comparisons
Timelines — historical events and milestones

Tips for Better Diagrams

Start with a template or use AI generation and modify from there
Use descriptive labels on nodes and edges for clarity
Keep diagrams focused — split large ones into multiple smaller diagrams
Use subgraphs in flowcharts to group related nodes
Try different themes to match your presentation style
Export as SVG for documents and PNG for presentations
Share your diagram via URL for quick collaboration

Whether you're documenting an API flow, designing a database schema, or planning a project timeline, SimplyUtils Mermaid Editor gives you everything you need — AI generation, live preview, zoom and pan, shareable URLs, and free exports. No sign-up, no paywall.