SiYuan

About

SiYuan is an open-source, privacy-first, self-hosted knowledge workspace where humans and AI agents work together. It is a personal knowledge management system that supports fine-grained block-level references and Markdown WYSIWYG editing.

Its features include block-level references and two-way links, custom attributes, SQL query embeds, a siyuan:// protocol, and a block-style editor with list outlines and block zoom-in, along with support for editing million-word large documents. It also offers mathematical formulas, charts, flowcharts, Gantt charts, and more, as well as web clipping, PDF annotation links, a database table view, flashcard spaced repetition, AI writing and Q/A chat via the OpenAI API, and Tesseract OCR.

SiYuan can be installed as a desktop app through the Microsoft Store or direct download, as a mobile app on iOS, Android, and HarmonyOS, or self-hosted via Docker. Most features are free, including for commercial use, though some are limited to paid members.