SiYuan

A privacy-first note and knowledge app with built-in AI.

Editorially reviewedChecked Oct 2026How we review·11 visited this week

note-taking#practical-oss#open-source#self-hosted#knowledge

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Free plan Self-hosted Offline mode

Toolglade’s take

A powerful, genuinely local-first block editor that holds its own against better-known PKM apps, especially if block references and offline ownership matter to you. It is best for tinkerers building a personal knowledge base who do not mind configuring things and supplying their own AI key; people who want official cloud sync will hit the paid membership, and the Docker/server mode drops features like PDF/Word export.

Should you use SiYuan?

Biggest strength: Local-first storage in open files you own, usable fully offline
Biggest weakness: Built-in AI writing and chat require your own OpenAI API key
Pricing: Free plan
Top alternative: Anytype · see all

Facts & pricing last checked October 2026. How we review

About SiYuan

SiYuan is a block-based note-taking and knowledge-management app with AI writing and question-answering built in. It keeps your data local by default, for people who want to own their notes.

SiYuan is a privacy-first, open-source personal knowledge management app built around content blocks. It offers block-level references and two-way links, a Markdown WYSIWYG editor, outlining, document trees, tables/databases, spaced-repetition flashcards, and SQL queries over your notes. Your data is stored locally as files (notes are saved as .sy JSON, with assets alongside), so you keep ownership and can work offline. It runs on Windows, macOS, Linux, Android, iOS, and HarmonyOS, and can also be self-hosted via Docker for browser access. AI writing and Q&A chat are built in through the OpenAI API. SiYuan is popular with people building a "second brain" who want block-based linking similar to tools like Obsidian or Logseq but with a strong local-first stance. It is AGPL-3.0 licensed, and most features are free even for commercial use; a paid membership adds extras such as official cloud sync. The AI features require you to supply your own API key.

Weighing your options?See how SiYuan compares to the alternatives.

Pros & cons

Pros

Local-first storage in open files you own, usable fully offline
Block-level references, two-way links, and SQL queries for deep organization
Most features are free, even for commercial use
Cross-platform: desktop, mobile, HarmonyOS, plus Docker self-hosting
Built-in flashcards, web clipping, and a community plugin/theme marketplace

Cons

Built-in AI writing and chat require your own OpenAI API key
Some conveniences, notably official cloud sync, are behind a paid membership
The Docker/server mode is browser-only and drops PDF/HTML/Word export and Markdown import
Documentation and UI occasionally show rough English, reflecting its origins