SiYuan is a privacy-first, self-hosted, fully open-source personal knowledge management system supporting block-level references, Markdown WYSIWYG editing, bidirectional links, and end-to-end encrypted sync.

---

🚀 Overview

SiYuan is a powerful note-taking and knowledge management app designed for users who prioritize data privacy and control. It allows organizing information at the block level, enabling fine-grained referencing, outlining, and linking that makes complex knowledge structures easy to build and navigate. Unlike cloud-dependent tools, SiYuan works completely offline, stores data locally as JSON files, and supports self-hosting via Docker for secure multi-device access.

What problem does this project solve? It addresses the limitations of proprietary PKM tools like Notion or Evernote by offering full data ownership, no vendor lock-in, and advanced features like spaced repetition for learning, AI integration, and database relations—all without compromising privacy. Who is it built for? Knowledge workers, students, researchers, and teams needing a robust, extensible system for managing notes, documents, and ideas. Why did you build it? The b3log team created SiYuan to provide an open-source alternative emphasizing privacy, block-level granularity, and seamless Markdown editing, filling gaps in existing tools for self-hosted, E2EE sync-capable PKM.

---

✨ Key Features

• Block-level reference & bidirectional links (backlinks, graph views) for discovering connections and refactoring knowledge structures
• Markdown WYSIWYG editor supporting million-word documents, formulas, charts, Gantt, tables, and zoom-in focus mode
• Spaced repetition (FSRS algorithm), databases with relations/rollup, templates, and flashcard mode for efficient learning and data management
• AI integration (OpenAI API for writing/Q&A), OCR (Tesseract), web clipping, PDF annotation, and exports to PDF/Word/HTML
• Optional: End-to-end encrypted sync (paid), multi-tab interface, plugins marketplace, custom JS/CSS snippets, mobile apps

---

🛠 Tech Stack

• Frontend: TypeScript, SCSS, HTML
• Backend: Go (kernel)
• Database: JSON blocks (.sy files), local filesystem
• Auth: Local/self-hosted (authorization codes for server access)
• Hosting: Self-hosted, Docker (b3log/siyuan), Electron for desktop

---

👥 Who Is This For?

This project is useful for:

• Knowledge workers who want to build interconnected note systems with full privacy
• Teams looking for self-hosted PKM with collaboration via Docker servers
• Indie makers and researchers building personal wikis with AI and spaced repetition

---

📸 Screenshots / Demo

• Live demo: No public demo; try via downloads or self-host
• GitHub: https://github.com/siyuan-note/siyuan (screenshots in /screenshots folder)

---

🔥 Project Status

• 🟢 Actively building

Last updated: 2026-03-24

---

❓ FAQ

Is this project free?

Freemium (Most features free including commercial use; paid membership for cloud sync, advanced AI/OCR usage)

---

Is the source code available?

Yes — https://github.com/siyuan-note/siyuan (AGPL-3.0 license)

---

Can I contribute?

Yes—check the Development Guide in the repo for UI/kernel/mobile contributions; open issues/PRs on GitHub; join community discussions.

---

📬 Contact & Links

• Website: https://b3log.org/siyuan/en
• GitHub: https://github.com/siyuan-note/siyuan
• Twitter/X: https://x.com/b3logos
• Email: support@b3log.org (via b3log community)

---

Built with ❤️ and kept warm on WarmIndex.