At a Glance:
SiYuan is a privacy-first, open-source personal knowledge management system offering fine-grained block-level referencing, Markdown WYSIWYG editing, and self-hosted deployment via Docker, with native apps for desktop and mobile platforms.
Overview:
SiYuan is an open-source personal knowledge management tool focused on privacy and local-first data ownership. It provides a block-level editor that combines Markdown WYSIWYG with bidirectional linking, allowing users to reference any content block individually. The system supports rich content types including mathematical formulas, diagrams, and embedded SQL queries. Users can run SiYuan on desktop, Android, iOS, and HarmonyOS, or deploy it as a self-hosted web application using Docker. The project is built around a local file-based data storage model with JSON-formatted documents, and it offers optional cloud storage connectivity for paid members. While most features are free for all uses, certain advanced capabilities such as AI-powered writing via OpenAI API and Tesseract OCR are available to paid subscribers.
Key Decision Points:
Self-hosted deployment: SiYuan can be run as a standalone web application through Docker, but this mode is limited to browser access and does not support desktop/mobile app connections or document exporting.
Local-first data storage: All data is stored in a workspace folder on the user's device as JSON files, giving users direct file-system access to their content without proprietary formats.
Paid feature boundaries: AI writing, OCR, and third-party cloud storage integration require a paid membership, while core editing, block referencing, and local-only use remain free.
Synchronization limitations: The project explicitly does not support data synchronization through third-party sync disks like Dropbox or Syncthing, advising against it due to potential data corruption.
Core Features:
Block-level referencing and two-way links: Every content block can be individually referenced and linked bidirectionally across documents.
Block-style Markdown WYSIWYG editor: The editor renders Markdown directly in a block-based interface with support for large documents over one million words.
SQL query embedding: Users can embed dynamic content using SQL queries within documents.
Flashcard spaced repetition: Built-in support for creating and reviewing flashcards with spaced repetition algorithms.
Community marketplace: A platform for discovering and sharing themes, templates, plugins, and code snippets contributed by the community.
Multi-platform apps: Native applications are available for desktop operating systems, Android, iOS, and HarmonyOS.
Use Cases:
Individual researchers and writers managing interconnected notes with fine-grained references between ideas and sources.
Self-hosted users who want a browser-accessible knowledge base running on their own server through Docker.
Students using the built-in spaced repetition flashcards to review study material alongside their structured notes.
Open-Source Alternative Value:
SiYuan provides a fully open-source codebase across its editor engine, desktop and mobile applications, and plugin API, allowing developers to audit or fork the entire system. Users can store all workspace data locally as JSON files, giving them direct access to their content outside the application. The project's Docker deployment option enables self-hosting a personal knowledge base on private infrastructure without depending on external cloud services. While certain convenience features like AI integration and official sync require a paid membership, the core editing, block referencing, and linking capabilities remain free and fully functional without subscription.
