How sync works
同期は、別のデバイスを招待したときにだけ行われます。
One device needs no relay. A relay is needed only when two or more devices sync.
Read about privacyInvites
This invite is created on your device and carries the key to this space. Only devices you share it with can join, and TallieUp never sees it.
Joining needs no TallieUp account: scan the QR code or paste the invite code.
Trusted devices are devices you invite by QR or code. They can view and update this space.
Only share with devices you trust.
What the relay does
The relay moves encrypted updates. It cannot read your budget contents.
Updates are encrypted on the device before they leave. The relay holds them while a device is offline. It checks each device by its signing key, with no passwords.
What the relay may see
| What the relay may see | What it can’t read |
|---|---|
| Your budget contents. Sync updates are encrypted on the device before they leave. |
Paired devices hold the keys and can read the shared records.
Removing a device
The other devices stop accepting changes from this device. It keeps the copy it already has, and anything it already added to the space stays. Only the space creator can do this.
The shared key isn’t rotated automatically.
Which relay
This space stays on this device until you set up sync. Anyone you invite will keep their own separate copy.
A space stays in sync across your trusted devices through a relay. You choose which relay carries the encrypted updates.
Keeping a shared space in sync needs a relay. The app offers two: TallieUp’s hosted relay, sold as an app store subscription, or a relay you run and point the space at.
Hosted sync is not a complete backup of this installation.
Technical details
| Part | How it works |
|---|---|
| Update encryption | XChaCha20-Poly1305, applied on the device |
| Device authentication | Ed25519 challenge-response; no passwords, no accounts |
| Relay | Store-and-forward WebSocket server; holds encrypted updates while a device is offline |
| Backup encryption | XChaCha20-Poly1305 with a key derived from the recovery code |
You can start with a demo plan.
When the app is available to you, its first screen offers four ways in. One is a demo plan.
Try a demo plan · Restore encrypted backup · Join with an invite · Create a new space
These are sample numbers, kept separate from your real plan.
Opens an email to hello@tallieup.io. No reply time is promised.