Files go straight from one device to the other (peer-to-peer WebRTC) whenever possible. They are never stored on any server.
If a direct link isn’t possible (common on mobile data), the already-encrypted pieces can pass through Ferry’s own relay on Cloudflare, which only the owner’s computer copy of Ferry can open. The relay can’t read or change your files, but it can see that two devices are connected, their internet addresses (which show roughly where they are), when, and roughly how much is sent.
Strong encryption, end to end. Ferry’s own AES-256-GCM with brand-new keys for every connection (forward secrecy), plus WebRTC’s built-in DTLS on direct links. Any tampered, dropped or replayed byte kills the connection.
The pairing code is the lock. It is single-use, random (95 bits) and never leaves your devices. A public relay (ntfy.sh) passes a few encrypted setup messages between them; without the code it can’t read, forge or redirect anything.
Security code. If both screens show the same six digits, nobody is in the middle.
Nothing is stored. Closing this page destroys all keys and any received file you haven’t saved.
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