Last updated: 2026-07-03
WeTransfer made sending big files feel effortless: drop a file, get a link, and the recipient downloads whenever they are ready — even if they were offline when you sent it. That asynchronous, no-account-to-receive experience is genuinely good, and it is why so many people reach for it.
This article compares the two fairly. WeTransfer's strength is polished, link-based sharing where the file waits on a server. Relayium's focus is different: realtime transfers that go directly between devices with no size cap and never land on a server, plus an optional stored link that stays zero-knowledge encrypted. Neither is simply better — they solve slightly different problems.
WeTransfer's core idea is asynchronous: the sender uploads once, gets a link, and the recipient downloads later. The two people never have to be online at the same time, which is exactly what you want when you email a video to a client who will open it tomorrow.
It is also mature and frictionless. There is nothing to install, the free tier lets you send without an account, and the interface is famously simple. For occasional link sharing within its size limit, it just works.
With WeTransfer, your file is uploaded to its servers, stored there for a while, and downloaded from there. The free tier caps each transfer at 2 GB, and the link points at a copy sitting on infrastructure you do not control. The transfer is encrypted in transit and at rest, but it is not zero-knowledge: the service holds the keys and could, in principle, read the file.
Relayium's realtime mode works the other way around. Bytes flow directly between the two devices over an encrypted peer-to-peer channel and are never parked on a server, so there is no server-side size cap to hit. On top of the WebRTC transport, Relayium adds its own layer: an X25519 key exchange derives a key for per-chunk AES-256-GCM, both devices show a matching 6-digit verification code (SAS) to rule out a man-in-the-middle, and each file is checked end-to-end with a SHA-256 hash.
Because nothing is stored on a server, the practical file-size limit comes from your own browser. In Chrome or Edge, Relayium streams incoming data straight to disk, so there is effectively no size cap — multi-gigabyte videos and project archives are fine.
Firefox and Safari do not yet offer the same streaming download, so there the browser buffers the file in memory; keep those transfers under about 200 MB for a smooth experience. Realtime transfers need no account at all: open relayium.com on both devices, pick up to 10 files, verify the code, and send. If a connection drops mid-way, the transfer resumes instead of starting over, and when a direct link is impossible it falls back to an encrypted TURN relay that only ever sees ciphertext.
Realtime transfer needs both people present, which is the one thing WeTransfer's link model does better. So Relayium offers the same async convenience without giving up privacy: a stored download link.
Your browser encrypts the files with AES-256-GCM before upload, and the decryption key lives only in the URL fragment — the part after the # that browsers never send to the server. The server therefore stores zero-knowledge ciphertext it cannot read, and the recipient does not need an account to download. Creating such a link requires the sender to sign in, and each link can be set to expire or to burn after the first download.
The differences that matter most, side by side:
In realtime mode there is no server-side cap, because the file never touches a server. In Chrome or Edge the download streams straight to disk, so multi-gigabyte files are fine. Firefox and Safari buffer in memory instead, so keep those transfers under about 200 MB. Stored download links have a quota tied to your account.
Use a stored download link. Your browser encrypts the files with AES-256-GCM, the key stays only in the URL fragment, and the server keeps zero-knowledge ciphertext the recipient can fetch later. Creating the link requires the sender to sign in, and you can set it to expire or burn after the first download.
Yes. Relayium is free and open source under the MIT license, with the full protocol and code at github.com/relayium/relayium. There is no paid tier to unlock larger realtime transfers — the size headroom comes from streaming to disk in the browser, not from a subscription.
Send a large file right now — no size cap, no install, and no account for realtime transfers.
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