siyuan-note/siyuan

SiYuan is a personal knowledge management application, think of it like a private note-taking and organizational system that you host entirely on your own devices, with no reliance on external cloud servers. The core problem it solves is that many note-taking tools store your data on someone else's servers, introduce privacy risks, and don't let you fully own or control your information. SiYuan takes the opposite approach: everything lives locally, and sync (if you want it) is opt-in. The distinctive feature of SiYuan is its block-based editing model. Rather than treating a document as a flat text file, every paragraph, heading, list item, and image is its own discrete block with a unique identifier. This allows you to create two-way links between specific blocks across different documents, so when you reference an idea in one note, that note knows it has been referenced from elsewhere. You can also embed database views, run SQL queries over your own notes, create flashcards for spaced repetition learning, attach math formulas, flowcharts, and Gantt charts, and annotate PDFs. There is a community plugin marketplace for extending the app further. You would use SiYuan if you want a serious, long-term personal knowledge base that you fully control, popular with researchers, students, writers, developers, and anyone who thinks carefully about how they organize information. It is also useful for people leaving tools like Evernote or Notion who want something local-first. The tech stack combines TypeScript for the frontend editor and Golang for the backend server. The desktop app is built on Electron (which wraps web technologies into a native window), and it also supports mobile apps for Android and iOS, plus Docker deployment for running it on a home server.