MermaidStudio — Free & Open-Source Mermaid Diagram Editor

Draw flowcharts, sequence diagrams, class diagrams, Gantt charts and mind maps directly in your browser — with a drag-and-drop visual editor, folders and version history, and an AI assistant that runs locally on your GPU. No account, no server: everything stays on your device.

• In-browser AI (WebGPU) — generate and fix diagrams with a local LLM; your code never leaves the machine.
• Visual editor — drag-and-drop nodes and edges over the live Mermaid preview.
• Organize — multi-tab workspace with folders, tags and full version history.
• Export & themes — SVG/PNG export with custom styling.
• Private by design — open source (MIT), no account, no telemetry, works offline (PWA), English and French.

Free & open source (MIT) · Runs entirely in your browser — even the AI · ★ GitHub · ☕ Ko-Fi · Liberapay