SiYuan, plainly

The thirty-second version#

SiYuan is an open-source personal knowledge base — a place to keep notes, documents, and small databases that all live as files on your own machine, not on someone else’s servers. People often reach for it when they want “Notion, but private and free.” That’s roughly right, with a twist: it borrows the best bits of three tools at once — Notion’s blocks and databases, Obsidian’s two-way links, and Anki’s flashcards.

The app is free — even for work use. A small paid membership only covers extras like the official encrypted cloud sync. You can also self-host it as a single container if you’d rather run your own sync.

Is it “free Notion”?#

Sort of — but it’s more accurately its own blend:

	SiYuan	Notion
Your data	Local files, yours	On their servers
Open source	Yes (AGPL)	No
Self-host	Yes	No
Backlinks · flashcards · SQL	Built in	Weak or missing
Real-time team collaboration	Weak — it’s single-user first	Its strongest feature

So: great if you want a private, own-your-data second brain. Not the tool if you need Notion’s shared-workspace, multiplayer side.

Why I found it interesting#

The privacy-first, files-on-disk design is the appeal — you’re never locked in, and it keeps working offline. Block-level links plus built-in spaced-repetition flashcards is an unusual, useful combination for anyone who studies or takes a lot of notes.

The honest catch#

It’s a China-origin project (a few China-specific export options, docs occasionally read as translated) — active and popular, just worth knowing. And “free” has an edge: the local app is fully free, but cloud sync is the paid part. Compared to something like World Monitor, though, the effort to use it is tiny — download the app and go; the optional self-hosted sync is one small container.

My read: a strong, honest alternative to Notion for personal knowledge work — noted here as something worth trying, not something we run.