Passkeys & Cross-Device Sync

Passkeys let you restore all your lists on any new device — no account, no email, no password required.

What is a passkey?

A passkey is like a digital key that lives on your phone or computer. It's protected by whatever you already use to unlock your device: Touch ID, Face ID, Windows Hello, or your PIN.

There's nothing to remember. You don't type anything. Your device confirms it's really you and the rest happens automatically.

Your fingerprint or face scan never leaves your device — ever. It only unlocks the private key locally, which then proves your identity to the server.

Why you stay completely anonymous

When you save a passkey, we store two things:

1. A cryptographic public key — like a padlock without the key. Mathematically useless without the matching private key, which stays on your device.
2. Your existing anonymous list ID — the same random code (like a3f7c2b8…) that was already in your browser. We didn't generate a new identifier. We just linked the one you already had to the public key.

We don't know who you are and we don't want to. No name, no email, no IP address is stored alongside your passkey.

Want to understand the full picture of what we store? Your data →

How cross-device sync works

Passkeys sync automatically through your existing accounts — you don't do anything extra:

• iPhone, iPad, Mac (iCloud Keychain): Sign into iCloud on any Apple device and your passkeys are already there.
• Android and Chrome (Google Password Manager): Sign into your Google account and passkeys follow you across all your Android devices and Chrome on desktop.

✅ Safari ↔ iPhone / iPad / Mac
Same Apple ID = same passkey everywhere

✅ Chrome + Google Password Manager
Same Google account = same passkey everywhere

✅ Safari → Chrome on the same Mac
Chrome 118+ can use iCloud Keychain passkeys

⚠️ Firefox. Passkey support incomplete; falls back to server backup + JSON export

✅ New device from a different ecosystem (one-time)
Scan a QR code with your existing device; passkey is then available there too

How to set it up

1. Go to the home page and make sure you have at least one list.
2. Accept the server backup offer if you haven't yet (the banner at the top of the page).
3. When the passkey offer appears, click "Save passkey".
4. Your device will ask you to confirm with Touch ID, Face ID, or your PIN.
5. Done — your lists are now linked to this passkey.

How to restore your lists on a new device

1. Open shared-lists.com on the new device.
2. Click "Restore with passkey".
3. Your device shows the saved passkey (already synced via iCloud or Google).
4. Confirm with Touch ID, Face ID, or your PIN.
5. Your lists appear and the server backup becomes active on this device too.

What if passkeys aren't available on my browser?

Older browsers and some Firefox versions don't support passkeys yet. In that case, the passkey option is simply hidden — nothing is broken.

Your lists are still backed up via the server backup (if you enabled it) and you can always export them as a JSON file.

Your data →

Frequently asked questions

What if I lose all my devices? Without any device that has the synced passkey, recovery is only possible via a previously saved JSON export that contains your device key.

Can I register the same passkey on multiple devices? In practice you don't need to — iCloud and Google sync handle this automatically. But if you manually register on a second device, both passkeys link to the same lists.

Can I delete my passkey? Yes. Delete it from your device's password manager (iCloud Keychain settings or Google Password Manager). This removes it from your device, but your lists remain on the server under the cookie backup as long as that cookie still exists.