head to head · open source
Mermaid vs plotly.js
Mermaid has 90,293 GitHub stars, 9,266 forks, 1,781 open issues and last shipped 3 days ago. plotly.js has 18,337 stars, 2,031 forks, 769 open issues and last shipped 2 days ago. Mermaid leads on adoption by 392% (90,293 vs 18,337 stars). Mermaid is written in TypeScript under MIT; plotly.js is written in JavaScript under MIT. Mermaid has attracted 10% as many forks as stars, plotly.js 11%. plotly.js was the more recently maintained of the two, and both are self-hostable with no licence fee.
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 | plotly.js | |
|---|---|---|
| GitHub stars | ★ 90K | ★ 18K |
| License | MIT | MIT |
| Written in | TypeScript | JavaScript |
| Last push | 2026-09-15 | 2026-09-16 |
| Forks | ⑂ 9.3K | ⑂ 2.0K |
| 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 plotly.js if
- You want the plotly.js feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches JavaScript
- You evaluated both and plotly.js 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 plotly.js
Plotly.js is an open source JavaScript charting library that renders interactive figures in the browser and also powers the Python and R packages named plotly in those ecosystems.
read the full plotly.js overview →
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Frequently asked questions
Is Mermaid or plotly.js more popular?
Mermaid has 90,293 GitHub stars and plotly.js has 18,337. Mermaid has the larger community by that measure.
Are Mermaid and plotly.js free?
Both are open source. Mermaid is licensed under MIT and plotly.js under MIT. Neither carries a licence fee.
What is the difference between Mermaid and plotly.js?
Mermaid is written in TypeScript and plotly.js in JavaScript. 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 plotly.js?
Choose Mermaid if you want the larger community (90,293 stars) or its MIT licence terms. Choose plotly.js if its feature set, stack or MIT licence fits better. Both are self-hostable.