head to head · open source
Mermaid vs datalens
Mermaid has 90,293 GitHub stars, 9,266 forks, 1,781 open issues and last shipped 3 days ago. datalens has 1,702 stars, 117 forks, 53 open issues and last shipped 25 days ago. Mermaid leads on adoption by 5,205% (90,293 vs 1,702 stars). Mermaid is written in TypeScript under MIT; datalens is written in PLpgSQL under Apache-2.0. Mermaid has attracted 10% as many forks as stars, datalens 7%. 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 | datalens | |
|---|---|---|
| GitHub stars | ★ 90K | ★ 1.7K |
| License | MIT | Apache-2.0 |
| Written in | TypeScript | PLpgSQL |
| Last push | 2026-09-15 | 2026-08-24 |
| Forks | ⑂ 9.3K | ⑂ 117 |
| 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 datalens if
- You want the datalens feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches PLpgSQL
- You evaluated both and datalens 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 datalens
DataLens is an Apache 2.0 open source business intelligence and data visualization system. It lives in the data and analytics ecosystem, specifically within business intelligence and reporting, and it covers dashboards, SQL, reporting, and visualization. The project was developed and extensively used as a primary business intelligence tool in Yandex, and it is also available as part of the Yandex Cloud platform.
read the full datalens overview →
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Frequently asked questions
Is Mermaid or datalens more popular?
Mermaid has 90,293 GitHub stars and datalens has 1,702. Mermaid has the larger community by that measure.
Are Mermaid and datalens free?
Both are open source. Mermaid is licensed under MIT and datalens under Apache-2.0. Neither carries a licence fee.
What is the difference between Mermaid and datalens?
Mermaid is written in TypeScript and datalens in PLpgSQL. 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 datalens?
Choose Mermaid if you want the larger community (90,293 stars) or its MIT licence terms. Choose datalens if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.