FlowViz

FlowViz is a free Mermaid diagram editor that runs in your browser. Write Mermaid syntax and see the diagram render as you type, or edit flowcharts directly on the canvas. Change a node's label, shape or colour, and the Mermaid source updates to match.

It supports every Mermaid v11 diagram type: flowcharts, sequence, class, state, ER, Gantt, mindmaps, timelines, C4, architecture, kanban and more (21 in total). Export as SVG or PNG, pick one of ten themes, or share a link that carries the whole diagram in the URL.

There's no account and no paywall. Diagrams are saved in your browser's local storage and are uploaded only if you choose to create a short link.