Does Linwood Butterfly Work Offline and How Do You Sync Your Notes?

Yes. Linwood Butterfly is local by default: your documents live on your device and keep working without an internet connection. Syncing is optional and self-directed — you connect your own WebDAV service, such as Nextcloud, to sync, back up, and edit notes across devices. There is no built-in cloud account mentioned in the site's description, so offline use is the baseline and sync is something you bring yourself.

Offline by default

According to the site, Butterfly is designed so you can "keep working without an internet connection," and documents stay on your device "unless you choose to save them somewhere else." That means:

• You can write, sketch, annotate, and organize on the infinite canvas with no connection.
• Your files are not uploaded anywhere by default.
• Nothing about offline use requires a login or an account.

This matters if you take notes in a lecture hall, on a plane, or anywhere with unreliable Wi-Fi — the canvas keeps working and your work stays put.

How syncing works: bring your own cloud

Butterfly does not appear to ship its own sync service. Instead, the site says you can "Connect WebDAV services like Nextcloud to sync, back up, and edit your notes anywhere."

In practice, that means the sync path looks like this:

1. You already have (or set up) a WebDAV-capable service, such as a Nextcloud instance.
2. You connect Butterfly to that service.
3. Your documents sync through your own storage, so you control where the data lives.

The trade-off is explicit: you get full ownership and no vendor lock-in, but you are responsible for having and maintaining the WebDAV server. If you do not already run one, that is the main setup cost.

File formats keep your work portable

Butterfly keeps documents in its documented .bfly and .tbfly formats. Because the formats are documented and the software is open source under the GNU AGPL-3.0 license, your notes are not trapped in a closed system — you can keep, move, and manage the files yourself, which pairs naturally with storing them on your own WebDAV server.

Collaboration is separate and experimental

If you want to work with others rather than just sync your own devices, the site describes experimental collaboration with end-to-end encrypted sessions, run either through Swamp or a WebSocket server you host yourself. Treat this as a distinct, experimental feature rather than a standard sync option — it is for live shared sessions, not for routine backup.

Which setup fits you

The short version: offline is the default and always available; cross-device sync is opt-in through your own WebDAV storage, so plan for that server if you want your notes on more than one machine.