SiYuan

Overview

SiYuan is a Markdown-based personal knowledge system for people who want notes, databases, and review cards to work together. It is a strong fit if offline use, data control, or self-hosting matters; the unclear paid-plan terms make a free start easier to recommend than an immediate subscription.

Key features

SiYuan builds documents from 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 useful for tracing connections across a knowledge base. That structure can be powerful for research and linked notes, but may feel like unnecessary machinery if you mainly want a simple place to write.

Databases support relations, rollups, and templates, and flashcards use the FSRS spaced-repetition algorithm. This combination suits users who want to organize information and revisit it over time without treating notes, structured records, and study material as separate workflows.

The maker says dynamic loading supports smooth editing of documents with millions of words on ordinary computers. OpenAI-powered tools can continue writing, translate, summarize, brainstorm, and correct grammar and spelling. Amazon S3-compatible storage and WebDAV are supported for sync and backup integrations.

The privacy policy says SiYuan does not collect personal information or usage data, and that data stays on the user's device under their control. The maker describes multi-device sync as incremental and end-to-end encrypted. Users can also deploy SiYuan with Docker on a server, controlling access through an authorization code. The app is open source, and most features are free for commercial use. Notebook documents use .sy files in JSON format.

Pricing

The Free plan costs nothing (billed $0 Lifetime) and includes basic functions with local storage. It is the sensible starting point for anyone who can keep data locally and does not need the paid sync integrations or cloud storage.

PRO Features costs $64 a month (billed Pay once, use for life). It includes basic functions and third-party S3 and WebDAV data sync and backup integrations, but third-party storage is not included. The price and billing description do not align clearly, so confirm the actual payment terms before buying.

Subscription costs $148 a month; the pricing page displays Lifetime, while the FAQ also refers to an annual subscription. It includes 8GB cloud storage. This may suit users who want SiYuan's cloud storage, but the conflicting term and steep stated price make confirmation essential. The pricing FAQ says subscriptions are non-refundable.

A trial subscription can be enabled in SiYuan Desktop under Settings - Account.

Platforms

SiYuan supports Windows, macOS, Linux, iOS, Android, a web interface, and Chrome and Edge extensions. It also offers an API and Docker self-hosting. Offline access is supported, giving users options beyond a browser-only workflow.

Who it's for

Choose SiYuan if you want a structured, connected knowledge base with databases and spaced repetition, and value local control, offline access, or self-hosting. Look elsewhere if you want a conventional note-taking app without block-level organization, or if you need simple, unambiguous subscription terms before committing.

Pros and cons

Pros

• Deep knowledge structure: Blocks, references, backlinks, and relationship graphs support connecting information at multiple levels.
• Notes and study tools together: Databases and FSRS flashcards add structured records and spaced repetition to the same system.
• Control over data: Local storage, offline use, encrypted sync, open-source code, and Docker self-hosting offer several ways to keep data under user control.
• Usable free foundation: Basic functions and local storage are available on the lifetime free plan.

Cons

• Paid terms are hard to reconcile: The PRO plan pairs a monthly price with pay-once, lifetime billing, while Subscription pairs a monthly price with Lifetime and annual language.
• Cloud storage is limited: The Subscription plan includes 8GB, and the PRO plan excludes third-party storage itself.
• Structure may be excessive for simple notes: The block-and-graph approach is best justified when users will make use of connected information and databases.

Alternatives

Logseq is worth choosing instead if free personal use is the priority: its Free plan is forever for personal use, while Sync Backer costs $5 a month as a recurring donation for beta sync access.

Obsidian may suit users comparing note-taking options who want to consider its Sync Standard plan, priced at $5 a month billed annually per user, with one synced vault, 1 GB total storage, and a 5 MB maximum file size.

Supernotes is an alternative for a card-based note workflow: its Starter plan includes 100 cards, and Unlimited costs £6 a month billed £72 billed annually.

TheBrain is another freemium option; its Free App plan offers unlimited thoughts, links, and brains, plus private sync for up to 1,000 thoughts and 100 MB synced attachments.

TiddlyWiki is a free and open-source alternative if that is the main criterion.

Capacities may be a better match for users weighing media-upload allowances: its Basic plan includes 5 GB of total media uploads, then 100 MB per month afterwards, while Pro is 9.99 USD.

Neoma offers a free Personal plan described as covering every feature and platform with no account, limits, or expiry; its Team plan costs A$22 a month.

Mem Agent is another freemium alternative.

Browse more options in Personal Knowledge Management Software and Note-taking apps.

Verdict

SiYuan is a compelling choice for people who want linked, block-based notes alongside databases and spaced-repetition cards, especially when local control or self-hosting is important. Start with the free local plan if it meets your needs; choose another tool or resolve the billing terms first if you need a straightforward paid subscription or included cloud storage beyond the stated 8GB.