head to head · open source
Mermaid vs lets-plot
Mermaid has 90,299 GitHub stars, 9,266 forks, 1,781 open issues and last shipped 4 days ago. lets-plot has 1,782 stars, 60 forks, 145 open issues and last shipped 3 months ago. Mermaid leads on adoption by 4,967% (90,299 vs 1,782 stars). Mermaid is written in TypeScript under MIT; lets-plot is written in Kotlin under MIT. Mermaid has attracted 10% as many forks as stars, lets-plot 3%. Mermaid 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 | lets-plot | |
|---|---|---|
| GitHub stars | ★ 90K | ★ 1.8K |
| License | MIT | MIT |
| Written in | TypeScript | Kotlin |
| Last push | 2026-09-15 | 2026-07-02 |
| Forks | ⑂ 9.3K | ⑂ 60 |
| 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 lets-plot if
- You want the lets-plot feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches Kotlin
- You evaluated both and lets-plot 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 lets-plot
Lets Plot is a multiplatform plotting library built on the principles of the Grammar of Graphics, maintained as an official JetBrains open source project for Python, Kotlin and JVM developers who need composable statistical graphics inside notebooks, IDEs and desktop applications.
read the full lets-plot overview →
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Frequently asked questions
Is Mermaid or lets-plot more popular?
Mermaid has 90,299 GitHub stars and lets-plot has 1,782. Mermaid has the larger community by that measure.
Are Mermaid and lets-plot free?
Both are open source. Mermaid is licensed under MIT and lets-plot under MIT. Neither carries a licence fee.
What is the difference between Mermaid and lets-plot?
Mermaid is written in TypeScript and lets-plot in Kotlin. 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 lets-plot?
Choose Mermaid if you want the larger community (90,299 stars) or its MIT licence terms. Choose lets-plot if its feature set, stack or MIT licence fits better. Both are self-hostable.