Mermaid Live Editor
FreeDraw flowcharts, sequence diagrams, ER diagrams, and more using text. Real-time preview, shareable links. The diagrams-as-code tool loved by developers documenting systems.
How to install Mermaid Live Editor as a PWA
Frequently asked questions about Mermaid Live Editor
Is Mermaid really diagrams-as-code that works in GitHub?
Yes — GitHub has rendered Mermaid code blocks natively in Markdown since 2022. Wrap Mermaid syntax in a ```mermaid fenced block and it renders as an SVG diagram on GitHub.com, in PRs, issues, and READMEs. GitLab, Notion, Obsidian, and most modern static-site generators (Docusaurus, MkDocs Material, Astro Starlight) also support Mermaid natively. The live editor is the place you draft and tweak before pasting into source control.
Is Mermaid Live Editor free?
Yes — Mermaid Live Editor is fully free with no account. It is maintained by the Mermaid open-source organization (the project that develops the Mermaid library itself). There is no paid tier on the editor. A separate commercial product called Mermaid Chart ($6+/month) by the same maintainers adds team libraries, AI features, persistent storage, and Figma/Confluence integrations — but the free editor remains the core tool.
How does Mermaid compare to PlantUML?
Mermaid runs entirely in the browser via JavaScript, has native GitHub/GitLab rendering, and has a simpler syntax for the most common diagram types. PlantUML requires a Java server or service for rendering, supports more diagram types (deployment, network, archimate, gantt with hierarchies), and has a longer track record in enterprise. For engineers, Mermaid usually wins because of native Markdown integration; for enterprise architects needing UML rigor, PlantUML is still the deeper tool.
Can I use Mermaid Live Editor offline?
Yes — the editor caches as a PWA and the Mermaid rendering library runs entirely client-side. Drafting, previewing, and exporting all work offline. The shareable-link feature requires network only for sharing; the diagram source is encoded directly in the URL fragment, so you can paste any historical URL and edit offline.
Who uses Mermaid in production?
Mermaid is the de facto diagram language of modern engineering documentation — used inside GitHub READMEs, ADRs, RFCs, GitLab wikis, Notion engineering docs, Obsidian vaults, and every modern docs-as-code site. Companies like Microsoft, Atlassian, and Stripe use it in public engineering content. The Live Editor is the canonical authoring tool, with the Mermaid-to-Excalidraw bridge making it easy to convert text diagrams into editable visual shapes.
Where Mermaid Live Editor is heading (12-24 months)
- →AI-assisted diagram generation (text prompt to Mermaid syntax) is shipping incrementally in Mermaid Chart.
- →Deeper C4 model support is on the roadmap, addressing the most common architect feature request.
- →Performance work on very large diagrams (hundreds of nodes) remains a constraint; SVG-to-Canvas rendering paths are being explored.
- →Tighter Excalidraw / FigJam two-way conversion would make Mermaid the canonical interchange format for technical diagrams.
Related questions
ChatGPT, Perplexity and Gemini usually suggest these next.
- How do I render Mermaid diagrams in GitHub READMEs?
- Does Mermaid support C4 architecture diagrams?
- How do I export a Mermaid diagram as PNG?
- Can I use Mermaid syntax in Notion?
- How do I theme a Mermaid diagram with custom colors?
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