Why You'll Love This Mermaid Diagram Generator
Let's be honest: drawing architecture diagrams or flowcharts by hand can be incredibly frustrating. Every time you add a new step, you have to manually drag shapes around, realign all the arrows, and fix the layout. That's why developers love Mermaid.js—it lets you generate diagrams using simple text.
But what if you don't want to learn all the Mermaid syntax from scratch? We built this online Mermaid Diagram Generator to give you the best of both worlds. You can write the code yourself, load up a pre-built template, or—even better—just ask our AI to generate the diagram for you!
New: AI-Powered Diagram Generation ✨
Not a Mermaid syntax expert? No problem. We've integrated a seamless AI Generate tool. Just click the Sparkles button in the toolbar, type in what you want (like, "Create a sequence diagram for a user login flow with 2FA"), and we'll instantly set up a prompt for ChatGPT to write the exact Mermaid code you need. Copy it, paste it into our editor, and you're done in seconds!
Everything You Need to Build Fast
We've packed this editor with powerful tools so you can focus on your documentation, not wrestling with formatting:
- Instant Live Preview: As you type, your diagram updates instantly in real-time. No need to click "Refresh."
- Rich Templates: Don't start from scratch. Use our built-in templates for ER Diagrams, Sequence Diagrams, Gantt Charts, and Architecture Flows.
- 1-Click Layout Changes: Want your flowchart to go Left-to-Right instead of Top-Down? Just use the handy Direction dropdown in the toolbar.
- Format Conversions: Seamlessly convert simple flowcharts into JSON or ASCII File Trees with the click of a button.
Export Perfectly Padded High-Res Images
Once your diagram looks perfect, exporting it is a breeze. We know how annoying it is when exported images clip the edges of your flowchart, so we automatically add a beautifully balanced 32px padding to all our exports.
You can download a crisp, scalable SVG (perfect for websites) or a high-resolution PNG (great for presentations and Slack). You can even customize the box border radius and line widths before exporting!
The Fastest Way to Update Your GitHub README
If you're building open-source projects, you probably want to embed these diagrams directly into your GitHub README.md. We added a super convenient Copy MD button. One click copies your diagram perfectly wrapped in \`\`\`mermaid tags. Just paste it straight into GitHub, and it will render natively!
Quick Crash Course: Understanding a Mermaid Flowchart
If you want to write it by hand, the syntax is actually quite friendly! Here's a quick look at how a simple flowchart is built:
graph TD
A[Christmas] -->|Get money| B(Go shopping)
B --> C{Let me think}
C -->|One| D[Laptop]- graph TD tells Mermaid you want a flowchart that goes from Top to Down.
- A[Christmas] creates a rectangular box with the text "Christmas" inside. The "A" is just an ID so you can reference it later!
- --> creates an arrow connecting two boxes.
- |Get money| adds a text label right on top of the arrow.
- C{Let me think} creates a diamond-shaped decision node (perfect for branching logic).
Built-In Diagram Themes
Different projects require different visual styles. The editor includes multiple Mermaid themes that can be applied with a single click, allowing you to preview how the same diagram looks across different designs:
- Default – Mermaid's standard appearance.
- Dark – Optimized for dark interfaces and technical documentation.
- Forest – A cleaner style with green accents.
- Neutral – Minimal styling for professional documents.
- Base – A simple foundation for custom diagram styling.
Switching themes does not modify your Mermaid code. It only changes the visual presentation of the rendered diagram instantly!
Who Is This Tool For?
The Mermaid Diagram Generator is designed for developers, technical writers, software architects, educators, DevOps engineers, and anyone who needs to create diagrams from text. It is particularly useful for GitHub documentation, project planning, system architecture diagrams, workflow visualization, and technical tutorials where diagrams need to stay synchronized with source-controlled documentation.