The diagram editor that gets out of your way.

FlowViz is a free, browser-based editor for Mermaid — the text-to-diagram language used in READMEs, wikis, and docs everywhere. Write syntax on the left, watch the diagram render live on the right, export clean SVG or PNG when you're done. Every diagram type in Mermaid v11 is supported, and the syntax cheatsheet and examples library cover all of them with copy-paste-ready code.

Why it exists

Most diagram tools want an account, a subscription, or your data. FlowViz wants none of those. It started as an internal tool for writing architecture diagrams faster and became a product with three rules: no signup, no paywall, and no copy of your work on anyone's server. Diagrams live in your browser's localStorage and nowhere else — the privacy policy is short because there is genuinely little to disclose.

What it covers

All 21 diagram types documented on the cheatsheet work in the editor: flowcharts, sequence, class, state, and ER diagrams, Gantt charts, git graphs, pie charts, mindmaps, timelines, quadrant, sankey, XY, block, and architecture diagrams, user journeys, requirement and C4 diagrams, kanban boards, radar charts, and packet diagrams. FlowViz is actively maintained — the cheatsheet and examples are kept current with Mermaid releases.

Who's behind it

FlowViz is built and maintained by the FlowViz team. Questions, bug reports, or feature requests: support@flowviz.app.