head to head · open source
Mermaid vs diagram-design
Mermaid has 90,293 GitHub stars, 9,266 forks, 1,781 open issues and last shipped 3 days ago. diagram-design has 40,762 stars, 2,602 forks, 42 open issues and last shipped 3 days ago. Mermaid leads on adoption by 122% (90,293 vs 40,762 stars). Mermaid is written in TypeScript under MIT; diagram-design is written in HTML under MIT. Mermaid has attracted 10% as many forks as stars, diagram-design 6%. diagram-design was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (diagrams), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| Mermaid | diagram-design | |
|---|---|---|
| GitHub stars | ★ 90K | ★ 41K |
| License | MIT | MIT |
| Written in | TypeScript | HTML |
| Last push | 2026-09-15 | 2026-09-15 |
| Forks | ⑂ 9.3K | ⑂ 2.6K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Mermaid if
- You weight community size — 90K stars and counting
- You want the MIT license terms
- Your stack matches TypeScript
- You value the larger contributor base for long-term maintenance
pick diagram-design if
- You want the diagram-design feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches HTML
- You evaluated both and diagram-design fits your workflow better
About Mermaid
Mermaid is a JavaScript based diagramming tool that renders diagrams from Markdown like text definitions. It lives in the JavaScript/TypeScript ecosystem and operates both in the browser and in Node.js environments. The project’s core purpose is to eliminate the gap between software development and documentation by letting developers write diagrams alongside code, avoiding the rot and overhead of manual diagram maintenance.
read the full Mermaid overview →
About diagram-design
Diagram Design is a skill for Claude Code, Codex, Factory Droid, Pi, and other Agent Skills compatible hosts that generates editorial quality diagrams as self contained HTML and SVG, aimed at writers, engineers, and designers who need brand consistent visuals without opening Figma.
read the full diagram-design overview →
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Frequently asked questions
Is Mermaid or diagram-design more popular?
Mermaid has 90,293 GitHub stars and diagram-design has 40,762. Mermaid has the larger community by that measure.
Are Mermaid and diagram-design free?
Both are open source. Mermaid is licensed under MIT and diagram-design under MIT. Neither carries a licence fee.
What is the difference between Mermaid and diagram-design?
Mermaid is written in TypeScript and diagram-design in HTML. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Mermaid or diagram-design?
Choose Mermaid if you want the larger community (90,293 stars) or its MIT licence terms. Choose diagram-design if its feature set, stack or MIT licence fits better. Both are self-hostable.