Is Mermaid Free? A Plain-English Answer to Mermaid Pricing in 2026
Short answer: yes, Mermaid is free. Both the syntax and every popular editor built around it (mermaid.live, mermaideditor.com, the VS Code extensions, GitHub's renderer) cost nothing.
But "free" gets murky once a tool slaps "Pro" on a button. Here's what is actually free, what isn't, and where the lines are in 2026.
Mermaid the Library Is MIT Licensed
Mermaid itself is an open-source JavaScript library released under the MIT license. That means:
- Free for personal use
- Free for commercial use
- No attribution required (though it's polite)
- You can fork it, embed it in paid products, ship it inside enterprise software
Is mermaid.live Free?
mermaid.live is the official Mermaid Live Editor maintained by the Mermaid team. It is completely free with no signup. You paste code, you get a diagram, you export PNG or SVG. That's it.There's no premium tier, no usage cap, no ads. Diagrams render in your browser, so your code never hits a server.
Is Mermaid Editor (mermaideditor.com) Free?
Yes. mermaideditor.com is a free independent editor with a richer toolset than the official live editor: dedicated PNG, SVG, JPG, WEBP, and PDF exporters; a SQL-to-ERD converter; a PlantUML-to-Mermaid converter; and 21 language interfaces. No signup. No watermarks. No paid plan.
Diagrams are rendered locally in your browser. Nothing is uploaded.
Where Money Sometimes Enters the Picture
A few paid services build on top of Mermaid. Knowing what they charge for clears up most "is Mermaid free?" confusion:
- Mermaid Chart — A commercial SaaS by the Mermaid maintainers with collaboration, AI generation, and enterprise SSO. Has a free tier; paid plans start around $5–10/user/month. Not the same thing as the Mermaid library.
- Notion / Confluence / Linear — Render Mermaid for free inside their editors as part of their normal subscription. You're paying for the host platform, not for Mermaid.
- Some VS Code extensions — A handful of "preview pro" extensions exist, but the official Markdown Preview Mermaid Support is free.
What You Can Do For Free
- Write any kind of Mermaid diagram (flowchart, sequence, class, state, ER, Gantt, journey, mindmap, timeline, kanban, sankey, xychart, etc.)
- Export to PNG, SVG, JPG, WEBP, or PDF
- Embed Mermaid inside Markdown on GitHub, GitLab, Notion, Obsidian, VS Code
- Use it in commercial products
- Modify the source code
What's Not Free
Practically nothing in the core ecosystem. The exceptions worth flagging:
- Mermaid Chart's collaboration features (real-time editing, team workspaces, AI assistant) sit behind a paid plan
- Some hosted Mermaid renderers charge for high-volume API calls
- Commercial diagramming SaaS that happens to support Mermaid input (Lucidchart, etc.) charges for the platform, not the syntax
The Honest Recommendation
Use mermaid.live or mermaideditor.com. Write your diagrams. Paste them into your docs. Export when you need an image. There is no reason to pay for anything unless you specifically need real-time team collaboration on diagrams — at which point Mermaid Chart, Notion, or Confluence each cover that for a few dollars a month.
Mermaid being free is one of the reasons it won. The diagrams you write today will still render in five years on whatever Markdown platform you use, with zero licensing risk.