Duet: File Transfer & Share

Duet moves what matters from one phone to another — and gets out of your way.

Pick a file, a contact, a Wi-Fi password, a 2FA setup code, or any text. The
sender shows a QR code; the receiver scans it. For larger files, the two phones
connect directly over your local Wi-Fi network and the file streams across — no
upload, no size cap. Everything is end-to-end encrypted, and nothing ever
touches a server.

No account. No sign-up. No cloud. No cross-app tracking.

WHY DUET
• Reliable by design — built to finish the transfer, every time.
• Truly private — your data goes phone-to-phone, never through us. We can't see
it, because it never reaches us.
• Calm — no upsells and no "create an account" wall. Duet is free, supported by
small, non-personalized ads (no advertising ID, no cross-app tracking).

WHAT YOU CAN SEND
• Files of any kind — documents, photos, videos, archives. Streamed directly,
so size isn't a problem.
• Wi-Fi credentials — share your network without reading the password aloud.
• Contacts — send a contact card that drops straight into the other phone.
• 2FA / authenticator setup codes — move your TOTP seeds to a new phone.
• Plain text and links.

HOW IT WORKS
• Small items travel in a single QR code — scan and done, no network needed.
• Larger items use an animated QR sequence or a direct local-network link
between the two phones. Your data stays on your local network; it never goes
to the cloud.
• Every transfer is end-to-end encrypted. For local-network mode, both phones
pair securely — scan each way and you're done, with no code to compare.

PRIVATE BY DESIGN
• Your transfers never reach us — phone-to-phone, end-to-end encrypted, and
their contents are never written to permanent storage.
• No cross-app tracking and no profiling. Ads are non-personalized — no
advertising identifier (IDFA / Android Ad ID).
• To keep the app stable and improve it, Duet uses Google Firebase for crash
reports and anonymous, aggregate usage — only after you consent, and you can decline or turn it off any time in Settings. It never includes what you send.

Works phone-to-phone across iPhone and Android. iOS 15+ and Android 8+.