Compare / Capacities vs SiYuan

Capacities vs SiYuan

Capacities is an object-based notes studio where every note is a typed thing — a person, a book, a meeting; SiYuan is a free, open-source, block-based knowledge base with Notion-style databases and local storage. Here’s how they compare on pricing, platforms, linking, search, capture and collaboration — and how to decide between them.

What is Capacities?

Capacities organizes your knowledge by what things are. Instead of files in folders, you create objects — people, books, meetings, projects, quotes — each with its own properties and views, connected through backlinks and daily notes. Browsing by object type (every book you’ve noted, every person you’ve met) falls out of the design for free, and a calendar-centric daily view ties it to your day.

It’s a polished, cloud-based app on web, desktop and mobile, with a generous free core plan; Pro (about $10/month billed annually) adds the AI assistant, calendar sync and advanced queries. In July 2026 it shipped a developer API with OAuth, opening it up to integrations. One deliberate omission to know about: there is no collaboration, and the team has said it isn’t planned — Capacities is intentionally a personal tool.

What is SiYuan?

SiYuan packs a remarkable amount into an open-source (AGPL) package: block-level bidirectional links, WYSIWYG Markdown, Notion-like database and attribute views, spaced-repetition flashcards, a graph, PDF annotation and a plugin marketplace — all stored locally, with the option to self-host the whole thing in Docker. It’s free for personal and commercial use.

Sync is where money changes hands, modestly: a one-time PRO license (~$64) unlocks third-party S3/WebDAV sync, or you can subscribe to the official encrypted cloud service. The developer is China-based with a very active GitHub, and the app is fully usable in English. It’s single-player — no real-time collaboration — but as a personal all-in-one it rivals tools costing $100+/year.

Capacities vs SiYuan at a glance

Pricing and features as of mid-2026 — check each product’s site for current details.

Where Capacities shines

• Object types with properties give structure without the rigidity of databases or the chaos of free-form notes.
• One of the most polished, beautiful interfaces in the category, consistent across web, desktop and mobile.
• A genuinely useful free plan, with Pro at a mid-pack price.
• Daily notes plus calendar integration make it a natural journal-of-record.

Worth knowing: No collaboration — explicitly not supported and not planned; sharing is read-only page links. Cloud-first and proprietary, with no local-first storage or end-to-end encryption. Power features like queries sit behind Pro, and the object model can feel like ceremony for quick, messy capture.

Where SiYuan shines

• An unusually complete free feature set: block refs, databases, flashcards, PDF annotation, graph — no plugins required.
• Open source (AGPL) with local-first storage and Docker self-hosting.
• Sync your own way — one-time license for S3/WebDAV, or the official encrypted cloud.
• Very active development with a plugin bazaar on top.

Worth knowing: No collaboration and no first-party hosted sharing beyond exports and self-hosting. The interface is denser and less polished than Western commercial rivals, and documentation can be rough in translation. Capture from the web, email or feeds isn’t a focus.

Which should you choose?

Choose Capacities if:

• You think in entities — people, books, meetings — and want your tool to as well.
• Interface polish and aesthetics genuinely affect whether you’ll keep using a tool.
• You’re strictly solo and don’t need sharing or teamwork.

Choose SiYuan if:

• You want maximum capability for minimum (or zero) money, as open source.
• Self-hosting on your own infrastructure appeals to you.
• You want Notion-style databases and flashcards in a local-first app.

A third option: Dexi

If what you actually want is one searchable place for notes, bookmarks, newsletters and RSS — with tags, @mentions and [[wiki links]] that organize themselves as you write, semantic search that finds ideas even when the words don’t match, and an MCP server so Claude and other AI assistants can work with your notes directly — take a look at Dexi. It’s free for up to 1,000 notes, with no app to install.

• Dexi vs Capacities
• Dexi vs SiYuan

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