思源笔记

Quick Verdict

SiYuan is a local-first, block-based personal knowledge management system. Notes are kept on a device under the user’s control, and the core editor continues to work offline when a network or official cloud service is unavailable. Blocks, references, bidirectional links, outlines, databases, flashcards, and large-document handling make it closer to a programmable personal knowledge base than a basic cloud notebook. The project is open source and provides desktop and mobile clients.

Local-first needs a precise definition. Local editing does not create an off-site backup automatically, and data no longer exists only on one device after sync is enabled. Official sync, cloud asset hosting, third-party S3 or WebDAV, a Docker server, and an external AI API create separate data paths. Users retain substantial ownership and control, but also inherit responsibility for backups, secrets, conflicts, and vendor selection. SiYuan fits people willing to understand those boundaries.

Best For

SiYuan is best for writers, researchers, developers, and students who care about offline availability, data portability, and block-level connections. Users who can maintain backups, understand a workspace directory, and test restoration are positioned to benefit most. It also suits people who want databases, flashcards, backlinks, and a Chinese-first workflow in one client.

It is not automatically a mature real-time team document suite. A Docker deployment can provide shared access, but identity, concurrent editing, backup, upgrades, and availability remain the operator’s responsibility. Organizations handling customer records, intellectual property, or regulated data should evaluate endpoint security, identity, auditability, and external AI requests instead of treating the word local as a complete compliance answer.

Key Features

• Block editing: Documents, headings, lists, quotes, and other elements are organized as blocks that can be focused, rearranged, and referenced.
• Backlinks and graphs: Users can inspect backlinks, mentions, and block relationships while maintaining connections as content is reorganized.
• Databases: Relations, rollups, and templates support structured views for projects, reading, research, or personal records.
• Outlines and large documents: Headings and lists fold, while dynamic loading supports substantial documents.
• Flashcards and FSRS: Knowledge blocks can feed spaced-repetition review for study and long-term memory.
• Complete offline use: Core editing data remains on the local device, and basic functions do not require a cloud subscription.
• Optional sync and backup: A subscription supplies official sync and backup, while paid professional features can connect third-party S3 or WebDAV. These services are separate from local storage.
• External AI API: SiYuan’s official site describes OpenAI access for continuation, translation, summarization, brainstorming, correction, and questions. Selected content leaves the local application when such a service is called.

Use Cases

A reader can break notes into reusable blocks and connect concepts with links. A long-form writer can maintain sections through outlines and references. A student can turn selected blocks into flashcards. A project owner can use database relations to connect tasks and supporting material. AI can help rewrite or summarize selected content, but source interviews, papers, code, and meeting records should remain intact rather than being overwritten by generated prose.

For multiple devices, distinguish three functions. The local workspace is the active data, synchronization keeps devices consistent, and backup enables recovery from deletion, corruption, or ransomware. Sync does not replace backup. Before switching among official cloud, S3, or WebDAV, create an independent snapshot and test conflict handling and restoration with non-critical data.

Pricing

SiYuan’s official pricing page currently separates free basic functions, a one-time professional-feature purchase, and a subscription with official cloud services. The free level covers local core use. Professional features add integration with third-party S3 and WebDAV sync and backup, but users must obtain those storage services themselves. The subscription additionally includes official data sync and backup, cloud asset hosting, Cloud Inbox, and a stated amount of official cloud space.

This page avoids quoting the displayed discount because the official page shows changing list prices, promotional prices, and seat availability. Confirm currency, payment route, refund policy, cloud capacity, and account rules before purchase. A lifetime professional-feature purchase is not the same as buying official cloud resources. A subscription also does not remove the need for an independent backup. Third-party storage has its own cost, availability, and privacy terms.

Pros

• Local data and offline editing are core behavior rather than a premium afterthought.
• Blocks, backlinks, outlines, databases, and flashcards form a dense knowledge system.
• Open-source code and an accessible workspace give users substantial data control.
• End-to-end encrypted official sync and third-party storage options provide several paths.
• Large-document and Chinese-language workflows suit intensive writers.
• Users can select an AI endpoint instead of being locked to one built-in model.

Cons

• Local-first transfers more backup, endpoint security, and recovery work to the user.
• Local storage, sync, backup, official cloud, and third-party storage are easy to confuse.
• The block model and extensive settings create a learning curve.
• External AI APIs send selected content to another provider and weaken a purely local boundary.
• A self-hosted Docker server does not automatically provide enterprise identity, audit, or high availability.
• Multi-device conflicts and large attachment behavior need realistic testing.

Alternatives

FAQ

Where does SiYuan store notes by default?

Core note data lives in a local workspace on the user’s device. Follow the official guide for workspace paths and movement. Placing an active workspace inside an unsupported external sync folder can create concurrent writes or corruption.

Does local-first mean backups are unnecessary?

No. Devices can be lost, damaged, or compromised. Synchronization keeps working copies aligned and can propagate deletion; it is not an independent recovery copy. Maintain at least one separate backup and test restoration.

Are core note features available for free?

Yes. The official pricing page lists basic functions under Free. Third-party S3/WebDAV integration is a professional feature, while official sync, backup, and cloud resources belong to the subscription.

Does SiYuan run AI entirely on the device?

That should not be assumed. The official product page describes access to OpenAI. A configured external endpoint receives relevant prompts and content, subject to that provider’s data use, retention, region, network, and pricing terms.

How does official sync differ from S3 or WebDAV?

Official sync uses services and cloud space provided by SiYuan. S3 or WebDAV uses an account and storage selected by the user, with separate fees and availability. Both remain distinct from the local workspace and independent backups.

Does data ownership remove every privacy risk?

No. Device compromise, accidental sharing, leaked sync secrets, poor backups, and external AI processing can still expose content. Ownership is valuable only when combined with encryption, access control, backup, and selective disclosure.

Bottom Line

SiYuan builds a capable block knowledge system on local availability and user control, then offers optional sync, backup, and AI connections. Before adopting it, draw four explicit boundaries: active local workspace, synchronization service, backup destination, and model API. Preserve original sources, test recovery, and send only necessary content to external AI. That turns local-first from a slogan into an operational practice.