Settings

Cloud sync

How to sync canvases between devices, what gets encrypted, and how to recover if you lose your passphrase.

Updated 20 April 2026

Cloud sync is opt-in per notebook. You can sync one canvas while keeping another strictly local. Nothing moves until you tell it to.

Enabling sync on your first device

Open Settings → Privacy and enable Cloud sync.
Create or enter your sync passphrase. This is separate from your account password. The passphrase is used to derive the encryption key — and it is held only on your device, never on our servers.
Choose which notebooks sync. Right-click (or long-press) a notebook → Enable sync.

A small cloud icon appears on each synced notebook. A red variant means an error; a grey one means paused.

Adding a second device

Install Fluera on the second device.
Sign in with the same account.
Enter the same sync passphrase when prompted. The passphrase is not recoverable — if you don’t have it, the encrypted data is not readable on the new device.
Cloud sync begins. Expect the first full sync to take a few minutes for a moderately large notebook.

What is encrypted and how

Every notebook is encrypted locally with a per-notebook key.
Those keys are encrypted with a root key derived from your sync passphrase via PBKDF2-SHA256, 256,000 iterations.
Only the encrypted bytes ever reach the server. We cannot read your notebooks.

Metadata (notebook titles, timestamps, size) is also encrypted — the server sees opaque blobs and sync timestamps.

Losing your passphrase

If you forget your passphrase and you have no device that still has a cached key, your encrypted data becomes unrecoverable. This is by design. The alternative — a server-side recovery mechanism — would break the end-to-end model and is a trade-off we are not willing to make for consumer accounts.

For Education accounts, an optional administrator-held recovery key can be configured at deployment time. This is an explicit opt-in, documented on the institutional DPA, and audited.

Conflict resolution

If you edit the same canvas on two devices simultaneously while one is offline, Fluera uses a CRDT with vector clocks to merge without conflicts. You will not lose work. In rare cases where automatic merge is ambiguous, you will see a “merge needed” marker on the affected node and a side-by-side view to confirm.

Disabling sync for a specific notebook