Add a device
All of your devices share one sync account. Adding a device means handing it the credentials for that account, so the flow is built around two checks: a short check code you compare before connecting, and an emoji verification afterwards.
They do different jobs. The check code tells you the two screens are talking about the same account, room and server — it catches a code from somewhere else, which is the mistake people actually make. It is derived from those identifiers only, not from the password, so it says nothing about whether the credentials inside are still current, and nothing about who is on the other end. The emoji verification that follows is the step that authenticates the device, and until it completes the new device cannot read anything.
You need both devices in front of you. Start on one that is already connected — any of them, phone or desktop. There is no "main" device. If no device is connected yet, this page cannot help — your very first code comes from the server side instead: see Your first device.
Show the code on a device you already use
Open Settings → Sync Settings → Devices and choose Add device.
Treat what is on this screen the way you would treat your password, because that is what it contains. Anyone who scans or photographs the QR code can sign in to your sync account: they cannot decrypt your entries without also being emoji-verified from one of your devices, but they can take over the account — including changing its password and locking you out. Show it only to a device you own, and never send it through a chat, a screenshot or a shared screen.
Closing the sheet hides the code; it does not revoke it. The code encodes your current account password, so a photograph of it stays usable for as long as that password does. If you think someone captured it, treat it as a leaked password rather than as something that has since expired.
Copy pairing code is offered deliberately, for the case where the joining device has no camera — a desktop joining a desktop. It puts the same credentials on your clipboard, so paste them straight into the other device and nowhere else. Show pairing code as text displays the same code for reading off the screen instead.
Keep the sheet open. Below the code, a timeline follows the new device from Waiting for the new device… to Joined — confirm the emoji on both screens and Verified — ready to hand things off. If the sheet cannot check whether the new device has joined, choose Retry.
Scan it on the new device
Install Lotti on the new device, then open Settings → Sync Settings → Devices there and choose Set up sync. On a phone the camera opens straight away; point it at the first device. On a desktop, or if the camera is unavailable, choose Paste the code instead to use the copied code. A step track at the top — Get code, Check, Connect — shows where you are.
If this is the first device on your account, there is no other device to scan yet: Setting up your first device? on the same screen leads to Open the first-device guide.
Check the code matches before connecting
Decoding the code does not connect anything. What appears first is Compare before you connect: a review of what you are about to join, led by the check code. Both devices derive this code independently from the account, room and server. They never exchange it — which is what makes comparing it worth doing.
Look at the check code here and the one on the first device. They must be identical. The sync account and sync server below the code are context rather than things to compare — they do not appear on the other device. When everything matches, choose The codes match — connect.
If they differ, choose They don't match. Lotti warns that the code isn't from your device and does not connect; get a fresh code from your own device. A code you declined is recognized if you scan it again.
Finish the two steps that follow
Connecting joins the account. It does not yet give the new device the ability to read anything.
- Confirm the emoji. Both devices show seven emoji. Check they match and confirm on each. Until you do, the new device receives ciphertext it cannot read — encryption keys are only shared with devices you have verified. If no emoji appear, choose Check again, or start verification from Devices. See Verify the new device.
- Receive your settings. Back on the first device, the Add device sheet you still have open unlocks two hand-offs once the emoji match: Send settings delivers your categories, habits, dashboards and AI setup, and Send message history delivers the entries written before this device joined. Send both — the history is why a new device stops looking empty.
Leave both apps open until the first synchronization finishes. If you closed the sheet, the Devices page on the first device offers the same two hand-offs while it shows that the new device just joined. Otherwise, open Settings → Sync Settings → Maintenance there, choose Sync measurables, dashboards, habits, categories, AI settings, then Message history.
If something goes wrong
- The check codes differ. Do not connect. Reopening the sheet does not help by itself: the same account, room and server always produce the same code, so a mismatch means the two screens do not describe the same pairing.
- The code will not decode. Copy it again on the first device rather than editing what you pasted; the encoded value is not meant to be hand-corrected. If the app reports a version mismatch, the two devices are on different Lotti builds and both need updating.
- The code stopped working. A code no longer signs in once the account password changes. Choose Retry this code if the connection dropped, or Enter a new code and get a fresh one from your other device.
- The new device connected but stays empty. That is the expected state before verification. Finish the emoji comparison, send settings and message history, then check Sync devices for outbox and backfill status.
Continue with Sync devices for everyday status, delivery health and recovery tools.