Do my files go through your server?
Usually not: the two devices connect directly. When their networks allow no direct path (mobile data, strict firewalls), the data goes through our relay, still encrypted end to end, so the relay cannot read it, and it keeps nothing. Our server also helps the devices find each other: for at most two minutes it passes encrypted connection details it cannot read.
What does the safety code do?
Both screens show a six-digit code worked out from the encryption keys of this connection. If the codes match, nobody sits between the two devices. If they don't, stop the transfer.
Does it work between different networks?
Yes. The devices first try to reach each other directly, which works across most home and office networks. When that is impossible, the transfer goes through our encrypted relay instead, and the page says so. Only a firewall that blocks even the relay stops it; then another network helps.
Is there a size limit?
One file can be up to 16 GB. Before anything is sent, the receiving device checks that it has room for all the files, and says so if it doesn't.
Where do received files go?
Into this browser's own storage. They appear in My files under Received, where you can download them or open them in another tool.
Does it work on an iPhone?
In Safari 17 or later, yes, as long as the page stays open and in front. If the phone locks or you switch apps, the transfer stops and nothing unfinished is kept.
What does post-quantum mean here?
The keys are agreed with two methods at once: X25519, used everywhere today, and ML-KEM-768, a newer standard designed to resist future quantum computers. Recorded traffic stays private even if one of them is broken later.
