SiYuan

SiYuan is a knowledge workspace for people who want to connect notes, reference material and individual passages. Its block-based editor lets you link directly to a piece of text rather than an entire document.

• Linked notes: Connect blocks with references and bidirectional links, and read documents in outlines, focused block views or split panes.
• Research and writing: Write with visible Markdown formatting, include formulas and diagrams, clip web content and link to PDF annotations.
• Tables and flashcards: Organize information in database tables and review material with spaced repetition flashcards.
• AI assistance: Use writing tools and question-and-answer chat through the OpenAI API; these requests go to an external service.
• Exports and tool access: Export standard Markdown with assets, PDF, Word or HTML, and give other tools access to workspace data through an API or command-line interface.

SiYuan is open source under AGPL-3.0. Most features are free, including for commercial use, and some require payment. It has Android, iOS and HarmonyOS apps and supports self-hosting through Docker. The command-line interface can access workspace data without a running server.

Docker hosting provides browser access only: desktop and mobile apps can't connect to it. That deployment also lacks Markdown file import and PDF, HTML and Word export.