Last updated: 2026-07-09
Dropbox earns its reputation. It syncs a folder across every machine you own, keeps a version history when you overwrite something by accident, and makes it painless to hand a whole project folder to a client with a shared-link invite. If you want a working folder that just stays in sync, Dropbox does that job well and this isn't an argument against using it that way.
The friction shows up on a narrower job: you have one file, one recipient, and no ongoing need for it to live anywhere afterward — a signed PDF, a video export, a zip of photos. Dropbox still asks you to drop that file into your account, generate a share link, and think about who else has access to that folder. Relayium is built for that narrower job specifically: the file goes straight to the other person's device, or it becomes a link that decrypts only in their browser and disappears on a schedule you set.
Dropbox's core strength is that a folder you rely on is always current everywhere: edit a file on your laptop and it's already updated on your phone by the time you check. Selective sync, LAN sync for large local transfers, and file-recovery/version history all serve that same goal — a durable, dependable place for files you keep coming back to.
Shared folders and Dropbox Paper make it a solid pick for ongoing collaboration, and its link-sharing is genuinely convenient for small teams that already live in Dropbox day to day. None of that is what Relayium is trying to be — Relayium doesn't sync a folder or keep a working copy of anything.
To send one file through Dropbox, it first has to be inside Dropbox — uploaded to your account, sitting in a folder, before you generate a shareable link for it. That link points at a copy Dropbox is storing on your behalf, readable by Dropbox's own infrastructure and staying there until you go back and delete the file or revoke the link yourself.
For a one-off send, that's a lot of standing infrastructure for a file nobody needs to keep. Relayium's realtime mode skips storage entirely for the common case: bytes move directly between the sender's and recipient's devices over an end-to-end encrypted peer-to-peer connection, and the file is never written to a server at all. When you do want a link — because the recipient isn't online right now — the stored-link mode keeps a property Dropbox's sharing doesn't have: your browser generates a random AES-256-GCM key and encrypts the file with it before upload, and that key lives only in the URL fragment (the part after the #, which browsers never transmit to a server). Dropbox's servers can technically read what's in your account; Relayium's server, for a stored link, holds only ciphertext it has no way to decrypt.
When both people are online at the same time, realtime direct transfer sends up to 1,000 files in a single batch straight from one device to the other — no upload step, and nothing stored in between. Both sides get a matching 6-digit verification code (SAS) to catch any man-in-the-middle, every file is checked with a SHA-256 hash end to end, and a dropped connection resumes instead of restarting the whole thing.
There's no server-side size cap; the real ceiling is the receiving browser. Chrome and Edge stream incoming data directly to disk, so tens of gigabytes are no problem, while Firefox and Safari buffer in memory, so keep those transfers under roughly 200 MB. On the same network — say, sending to a coworker's laptop across the office Wi-Fi — no account is needed at all. Sending across different networks uses a pairing code and requires the sender to sign in; the recipient never needs an account either way. When a direct connection isn't possible, it falls back to an encrypted TURN relay that only ever sees ciphertext.
Sometimes a link genuinely is the right tool — the recipient is asleep in another time zone, or you want one URL to paste into an email instead of coordinating a live session. Relayium's stored-link mode is built for exactly that, without giving up the privacy of realtime mode.
You pick how long it lives — 1 hour, 1 day, 3 days, or 7 days — or set it to burn after the first completed download, so there's no lingering copy to remember to clean up. Creating the link requires the sender to sign in (it counts against a storage quota on the account), but the recipient just opens it and downloads — no Dropbox-style account required on their end. Because the decryption key never leaves the URL fragment, Relayium's server for a stored link is structurally unable to read what's inside it, which is a different guarantee than a Dropbox share link, where Dropbox's own infrastructure can technically decrypt the file it's hosting.
The differences most relevant to a one-off send:
Not with realtime transfer — the file moves directly between devices and is never stored on a server. A download link does store something server-side, but only zero-knowledge ciphertext the server can't decrypt, and it expires (1h/1d/3d/7d) or burns after the first download.
No. On the same network, neither side needs an account. Sending across networks by pairing code, or creating a stored download link, requires the sender to sign in — the recipient never needs an account, in either case.
Realtime transfers handle up to 1,000 files per batch with no server-side size cap — Chrome and Edge stream straight to disk for tens of gigabytes, while Firefox and Safari buffer in memory, so keep those under roughly 200 MB. Stored links count against a quota tied to the sender's account.
Yes. Relayium is free and open source under the MIT license, with the full protocol and code at github.com/relayium/relayium — there's no paid tier gating bigger or faster transfers.
Send the file directly, without putting it in anyone's account — no size cap, no install, and no account needed on the same network.
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