Diagram Generator
Turn plain text into flowcharts, sequence diagrams, and more.
About Diagram Generator
The Diagram Generator turns short, readable Mermaid text into polished diagrams — flowcharts, sequence diagrams, class and ER diagrams, state machines, Gantt charts, pie charts, and more. It's the fast way to document an architecture, an API call flow, or a database schema without dragging boxes around a canvas: describe the diagram in a few lines and it renders live as you type. Pick a diagram type to load a ready-made template, edit the text, and export the result as SVG or PNG to drop into a README, a design doc, or a slide. Rendering happens in your browser, so your diagrams stay on your machine. Pair it with the Markdown Previewer to embed the same Mermaid blocks in docs.
How to Use
- 1Open Diagram Generator and paste or type your data into the input area.
- 2Adjust any available options to match the result you want.
- 3Your output is generated instantly — no button-clicking required for most tools.
- 4Use the Copy or Download button to save your result.
Common Use Cases
- Sketching architecture and data-flow diagrams for docs and READMEs
- Mapping API request/response flows as sequence diagrams
- Modeling database schemas and class relationships visually
- Planning project timelines and processes as Gantt or flowcharts
Frequently Asked Questions
What diagram types are supported?
Flowcharts, sequence diagrams, class diagrams, entity-relationship (ER) diagrams, state diagrams, Gantt charts, pie charts, user-journey and Git graphs — anything Mermaid supports. Choose a type to load a starter template you can edit.
What syntax does it use?
It uses Mermaid, a plain-text diagram syntax. For example, a flowchart is just lines like `A[Start] --> B{Decision}`. Pick a diagram type from the dropdown to insert a working example you can adapt.
Can I export the diagram?
Yes. You can download the rendered diagram as a scalable SVG for crisp docs and print, or as a PNG image for quick pasting into slides, tickets, and chat.
Is my diagram data private?
The diagram renders entirely in your browser from the text you enter. The tool loads the Mermaid renderer from a CDN, but your diagram content itself is never uploaded to a server.
Is Diagram Generator free to use?
Yes. Diagram Generator is completely free with no sign-up, no subscription, and no usage limits. Every tool on CodeUtilityKit is free forever.
Is my data safe when I use Diagram Generator?
Absolutely. Diagram Generator runs entirely in your browser. Your input is processed locally with JavaScript and is never sent to, stored on, or logged by any server — so it is safe even for private or sensitive data.
Features
- Run Diagram Generator instantly, right in your browser
- 100% private — your data never leaves your device
- Copy the result to your clipboard in one click
- Free and unlimited with no account or sign-up
- Clear, friendly error messages when something is wrong
- Works on desktop and mobile, even offline after first load