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Local-first & sync

Brainstorm is local-first: your vault is on your disk, the app reads and writes it directly, and nothing about your own content requires a server. Sync is an option you turn on — not a dependency you depend on.

Local-first, in practice

Section titled “Local-first, in practice”
  • Instant. Opening a vault and editing objects is local disk speed — no round-trips.
  • Offline by default. Everything works with no network at all. You’re never blocked by a server being down or unreachable.
  • Durable. Your data is plain files you own. If you stopped using Brainstorm tomorrow, your vault is still right there on disk.

Conflict-free editing with CRDTs

Section titled “Conflict-free editing with CRDTs”

Brainstorm stores editable content as CRDTs (via Yjs). A CRDT lets two devices — or two people — edit the same object at the same time and merge the results automatically, with no “which version wins?” dialog. This is what makes offline edits and real-time collaboration both work without losing changes.

Sync that can’t read your data

Section titled “Sync that can’t read your data”

When you enable sync, Brainstorm connects your devices through a relay — but the relay is blind:

  • Your changes are end-to-end encrypted on your device before they’re sent.
  • The relay only stores and forwards encrypted CRDT traffic. It never holds your keys and cannot read your content.
  • The sync server is self-hostable if you’d rather run your own.

So you get multi-device sync and collaboration without handing your knowledge to a third party.

Restoring a device

Section titled “Restoring a device”

Because the encrypted history lives on the relay (or your own server), setting up a new device restores your vault from sync — you authenticate, and your objects rebuild locally from the encrypted stream.

Next steps

Section titled “Next steps”