head to head · open source
SiYuan vs Outline
SiYuan has 46,409 GitHub stars, 3,012 forks, 18 open issues and last shipped yesterday. Outline has 40,590 stars, 3,562 forks, 78 open issues and last shipped yesterday. SiYuan leads on adoption by 14% (46,409 vs 40,590 stars). SiYuan is written in TypeScript under AGPL-3.0; Outline is written in TypeScript under a custom or non-standard licence. SiYuan has attracted 6% as many forks as stars, Outline 9%. SiYuan 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
| SiYuan | Outline | |
|---|---|---|
| GitHub stars | ★ 46K | ★ 41K |
| License | AGPL-3.0 | Custom / other |
| Written in | TypeScript | TypeScript |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 3.0K | ⑂ 3.6K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick SiYuan if
- You weight community size — 46K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches TypeScript
- You value the larger contributor base for long-term maintenance
pick Outline if
- You want the Outline feature set and don't need the biggest community
- You prefer the Custom / other license terms
- Your stack matches TypeScript
- You evaluated both and Outline fits your workflow better
About SiYuan
SiYuan is an open source, self hosted knowledge management system built for privacy first workflows. It operates as a local first workspace where users store data in encrypted repositories on their own infrastructure, avoiding reliance on third party cloud services. The project lives in the productivity and utilities ecosystem, specifically targeting note taking and knowledge management use cases, and positions itself as a privacy respecting alternative to Notion.
read the full SiYuan overview →
About Outline
Outline is an open source knowledge base application built with React and Node.js, designed for teams needing a fast, collaborative documentation platform. It runs as a self hosted service or via a hosted option at getoutline.com, and its source code powers the public instance along with all supporting services. The project lives in the JavaScript/TypeScript ecosystem and uses MobX for state management.
read the full Outline overview →
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Frequently asked questions
Is SiYuan or Outline more popular?
SiYuan has 46,409 GitHub stars and Outline has 40,590. SiYuan has the larger community by that measure.
Are SiYuan and Outline free?
Both are open source. SiYuan is licensed under AGPL-3.0, and Outline has no licence declared in this registry. Both are free to self-host.
What is the difference between SiYuan and Outline?
SiYuan is written in TypeScript and Outline in TypeScript. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, SiYuan or Outline?
Choose SiYuan if you want the larger community (46,409 stars) or its AGPL-3.0 licence terms. Choose Outline if its feature set, stack or Custom / other licence fits better. Both are self-hostable.