SiYuan: The Block-First PKM Where Your Notes Never Leave Your Device

Notion stores everything on their servers. Obsidian sync costs $8/month. Roam Research is $15/month. Most PKM tools make you choose between convenience and data ownership. SiYuan does not. Block-level editing, bidirectional links, spaced repetition, relational database, AI writing, Docker deployment, E2EE sync. Local storage free forever. 45,000+ GitHub stars, AGPL-3.0, TypeScript + Go, v3.7.1 (July 2026).

What SiYuan is

SiYuan (b3log.org/siyuan, github.com/siyuan-note/siyuan) is a privacy-first personal knowledge management system. Built by Yunnan Liandi Technology (China). AGPL-3.0. TypeScript frontend, Go backend, Electron desktop. Windows, macOS, Linux, Android, iOS, HarmonyOS, Docker. Data stored locally by default.

The block model

Everything is a content block - paragraphs, headings, lists, code, quotes, embeds, database rows. You link to specific blocks, not documents. Referenced blocks update if the block moves. 20+ block types. Block zoom-in for focused editing. Million-word documents via dynamic loading. SQL query embeds. The siyuan:// protocol for deep linking from external apps.

Bidirectional links and graph

Block-level bidirectional links - backlinks appear at the specific block, not just the document. Unlinked mentions convertible to explicit links. Global relationship graph. Block-level focused graph showing link paths from any block. Both update in real time as you write.

Flashcards and spaced repetition

Any block becomes a flashcard. SiYuan uses FSRS (Free Spaced Repetition Scheduler) - the modern replacement for Anki's SM2, developed by open-spaced-repetition. Reviews scheduled by actual recall performance. Built into your notes. Anki deck import supported.

Database

Table view database with relation and rollup - Notion-like but local. Two databases linked via relation fields. Rollup aggregates across related records. Template columns, filter, sort, group. Database is a block, embeddable anywhere.

AI writing

OpenAI API integration in the editor. Continue writing, translate, summarize, brainstorm, grammar correction, Q&A chat. Your own API key. Works with any OpenAI-compatible endpoint including Ollama or LM Studio for local models.

Sync options

Official E2EE cloud (Subscription) - 8GB included, incremental, SiYuan team cannot read your data. Third-party S3 (PRO+) - Backblaze B2, Cloudflare R2, MinIO, AWS S3. WebDAV (PRO+) - Nextcloud, ownCloud. Docker server - browser access from any device, no cloud at all. LAN sync - desktop as local server, mobile via browser on same network.

Pricing

Free - local storage, all core features, forever. PRO ($64 lifetime) - S3 and WebDAV sync, pay once. Subscription ($148 lifetime) - PRO plus 8GB official E2EE cloud. One-time payments, no recurring subscription.

vs Notion and Obsidian

vs Notion: Notion stores data on Notion servers; SiYuan stores locally. Notion free tier then $10-15/user/month; SiYuan local is free forever. Notion database is more polished; Notion collaboration is better. SiYuan wins on data sovereignty and cost.

vs Obsidian: Obsidian is plain .md files on disk (more portable); SiYuan uses block model (more powerful fine-grained linking). Obsidian Sync is $8/month recurring; SiYuan sync is one-time or free via S3. Obsidian has larger plugin ecosystem.

Who it is for

Good fit: developers wanting Notion features with local-first data; Obsidian users wanting block-level referencing; Anki users wanting spaced repetition in their notes; anyone with data sovereignty requirements; self-hosters wanting a full PKM on their own infrastructure.

Not ideal: teams needing real-time collaborative editing; users requiring plain Markdown files on disk; users dependent on Obsidian's large plugin ecosystem.

My take

SiYuan's block model solves the core problem of file-based PKM tools: Obsidian's bidirectional links are file-level approximations. SiYuan's links work at block granularity because blocks are the foundation. The FSRS flashcard integration is genuinely useful - your notes and your review system live in the same place. The one-time lifetime pricing is the right model for a tool that holds your most important knowledge. You should not need an active subscription to access your own notes.