SiYuan

SiYuan is a personal knowledge management tool built around a single core idea: everything is a block. Documents, headings, paragraphs, lists, even pages themselves are all blocks you can reference, link, move, and reorganize without breaking existing connections. It's aimed at people who want a Logseq- or Obsidian-style networked knowledge system but with stronger privacy guarantees and a fully offline-capable architecture.

The editing experience is WYSIWYG with Markdown support. SiYuan ships with 20+ block-level element types and 10+ inline elements, covering most typesetting needs out of the box. Widget blocks handle more specialized cases. Large documents with millions of words load smoothly through dynamic rendering, so file size doesn't become a bottleneck.

Key capabilities:

• Bidirectional links at the block level, not just the page level. Backlinks show unlinked mentions, and a global relationship graph gives a visual map of how your knowledge connects.
• Database blocks with relation and rollup support, letting you link two databases and surface aggregated data across them.
• Spaced repetition flashcards built in, using an algorithm to schedule reviews based on memory decay.
• AI writing assistance for drafting, translation, summarization, grammar correction, and Q&A, accessed directly inside the editor.
• List outlines with folding, rich typography per item, and full integration with document structure.
• Zoom-in focus mode on any block, with breadcrumb navigation to keep context.

On the privacy side, all data lives on your device by default. Sync uses end-to-end encryption with incremental transfers to minimize bandwidth. No network connection is required to use it. SiYuan can also run as a local server accessible from a phone over a LAN, or be self-hosted via Docker for small-team collaboration with access controlled by an authorization code. For people comparing AppFlowy or AnyType, SiYuan's block-reference model and built-in spaced repetition are distinctive features that the others don't combine in one package.