SiYuan

SiYuan is a personal knowledge‑management system that stores all content as discrete blocks, allowing users to edit, reorganise and link information at a fine‑grained level. It supports Markdown formatting, block‑level references, bidirectional links, and a variety of built‑in block and line elements, enabling the creation of large documents, outlines, databases and flash‑card decks. The software runs locally, with optional end‑to‑end encrypted syncing across devices, and can be self‑hosted via Docker or other deployment methods.

The tool targets individuals who need a privacy‑first workspace for note‑taking, research, and learning, especially those who value offline access and control over their data. Features such as focus mode, dynamic loading for million‑character documents, and a global relationship graph help users navigate and visualise their knowledge network. Integration with OpenAI provides AI‑assisted writing, translation and summarisation.

SiYuan is released under the AGPL‑3.0 licence, is free to use without subscription, and is developed in TypeScript and Go. Its open‑source nature, self‑hosting capability, and emphasis on encrypted synchronization distinguish it from other note‑taking applications.