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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.

Sync over your local network

Section titled “Sync over your local network”

Two devices on the same Wi-Fi can also sync directly, with no server involved at all. Turn it on under Settings → Sync: devices discover each other on the local network, pair with a device-bound handshake, and exchange end-to-end encrypted changes peer to peer. It’s opt-in, and it composes with the relay — use either, or both.

Attachments follow you

Section titled “Attachments follow you”

Files and images attached to your notes and entities travel with your vault. Thumbnails are always synced, so previews appear instantly on every device; the full file downloads the moment you open it — nothing waits, and nothing hogs your disk.

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”