SiYuan

SiYuan is a personal knowledge system for notes, structured information, and spaced-repetition study. It suits people who want linked, block-based documents and the choice of local, cloud, or self-hosted use.

Its breadth is a strength, but the paid-plan wording needs careful checking before you commit.

Overview

SiYuan combines Markdown documents with block references, bidirectional links, databases, and flashcards. Offline access and Docker self-hosting give users control over where they work and keep their data; the trade-off is that the product’s many connected features may be unnecessary for someone who wants a simple notebook.

Key features

Content is organized into blocks, with more than 20 block-level element types and more than 10 span-level types. Block references, searchable and filterable backlinks, and global and block-level relationship graphs make it possible to navigate a knowledge base through its connections rather than only through folders or pages.

Databases support relations, rollups, and templates, while flashcards use the FSRS spaced-repetition algorithm. That pairing makes SiYuan a credible option for people who want structured records and study review alongside their notes.

The maker says dynamic loading allows documents containing millions of words to be edited smoothly on ordinary computers. AI tools use the OpenAI API for writing continuation, translation, summaries, brainstorming, and grammar and spelling corrections. Amazon S3-compatible storage and WebDAV are supported integrations.

SiYuan says it does not collect personal information or usage data and keeps data on the user’s device under their control. Its multi-device sync is described as end-to-end encrypted and incremental. Server self-hosting uses a Docker image, with access rights controlled by an authorization code.

Notebook documents use the.sy file format, with data stored as JSON. The download page describes the software as completely open source and says most features are free, including for commercial use.

Pricing

SiYuan is freemium, with a free plan at free (billed $0 Lifetime). It includes basic functions and local storage, making it the natural starting point for users who do not need the paid sync and backup integrations or cloud storage.

PRO Features is shown as $64 a month (billed Pay once, use for life). It adds third-party S3 and WebDAV data sync and backup integrations to the basic functions; third-party storage is not included. This plan may fit users who want those integrations and already have storage, but the monthly price label conflicts with the lifetime billing description.

Subscription is shown as $148 a month, with the pricing page displaying Lifetime while its FAQ also refers to an annual subscription. It includes 8GB cloud storage. The pricing FAQ says subscriptions are non-refundable, so readers should confirm the applicable term before paying.

Platforms

SiYuan supports Windows, macOS, Linux, iOS, Android, and a web interface, as well as a Chrome/Edge extension, API, and Docker self-hosting. Offline access makes it suitable for local work; note sharing is also supported. The combination of desktop and mobile apps with self-hosting is useful for people who want deployment choices beyond a single hosted service.

Who it's for

Choose SiYuan if you want a privacy-oriented knowledge base that connects block-level notes, databases, and flashcards, and you value offline access or the ability to self-host. It is less compelling if you need straightforward, unambiguous subscription terms or do not expect to use its structured linking and review tools.

Pros and cons

Pro: Block references, searchable backlinks, and relationship graphs support detailed connections across a knowledge base.

Pro: Databases and FSRS flashcards extend the same workspace to structured records and spaced-repetition review.

Pro: Offline access, encrypted sync, and Docker self-hosting give users several ways to manage access and data location.

Con: The paid plans’ monthly price labels conflict with lifetime and annual billing descriptions, complicating comparisons.

Con: The PRO Features plan excludes third-party storage, so users need to provide their own S3-compatible or WebDAV storage.

Alternatives

TheBrain is worth considering if you want a freemium option centered on thoughts, links, and brains, with private sync for up to 1,000 thoughts and 100 MB of synced attachments on its free app plan.

Heptabase may suit users who prefer a paid monthly plan with stated AI-credit allowances: Pro is $11.99 a month with 100 AI credits/month, while Premium is $23.99 a month with 1,800 AI credits/month.

Logseq is an alternative for personal use when a free, open-source-style option is the priority; its Free plan is free forever for personal use.

Obsidian may fit users seeking a freemium notes app with an explicitly priced annual Sync Standard plan: $5 a month, billed annually, per user, for one synced vault and 1 GB total storage.

SilverBullet is another free option for people who want a self-hosted and web-accessible notes setup.

Supernotes is a card-based alternative to consider if you want an Unlimited plan at £6 a month, billed £72 annually.

Tana may suit users looking for a freemium option with a stated allowance of five meetings, one calendar, and 50 AI queries on its Free plan.

TiddlyWiki is a free and open-source alternative for users who want a wiki that can also be self-hosted.

Browse Personal Knowledge Management Software or Note-taking apps for more options.

Verdict

SiYuan is a strong choice for people who want one system for connected notes, structured databases, and spaced-repetition cards, with offline use and self-hosting as meaningful control options. Its main reason to look elsewhere is the unclear paid-plan billing language; start with the free local plan, and verify the subscription term before buying.