Relayium

Relayium vs LocalSend: which local file transfer to use

Last updated: 2026-07-31

LocalSend is a genuinely good, well-loved app: free, open source, cross-platform, and built to move files between devices on the same local network with no server and no account, ever. A lot of people rely on it as an AirDrop-like tool for Windows, Linux and Android.

This article compares it fairly with Relayium, which tackles the same same-network problem a different way — no app to install, running right in your browser — and then goes further, reaching across networks and offering a command-line tool LocalSend doesn't have.

What LocalSend does well

LocalSend is a free, open-source app for Windows, macOS, Linux, Android and iOS. Install it once on each device, and it automatically discovers other LocalSend instances on the same Wi-Fi or LAN using an encrypted local transport — no server anywhere, no internet connection required, no account.

It supports drag-and-drop, sending whole folders, and an optional PIN for sending on networks you don't fully trust.

Where Relayium differs: nothing to install, right in the browser

Relayium takes the opposite approach to the same same-network problem: instead of installing an app on every device, you open relayium.com in a browser you already have. Two devices on the same network land in the same room automatically — the server derives the room from the shared network, with no pairing code and no account needed on either side.

That LAN room supports any number of peers at once, not just a pair, and drag-and-drop or folder selection works the same way a native app would — just without the install step.

Beyond the LAN: cross-network transfer and a CLI

LocalSend is local-network only by design — it has no way to reach a device on a different network or across the internet. Relayium adds that: create a pairing code (or share the join link it generates), and the other side connects from anywhere. In the browser, that cross-network hop deliberately runs over an encrypted TURN relay rather than hunting for a direct route — relay-only ICE brings the connection up in a second or two, instead of burning around 20 seconds on cross-NAT direct-candidate checks that would almost always fail anyway.

Creating a cross-network pairing code requires the sender to sign in; the person receiving never needs an account. Every realtime transfer — LAN or cross-network — is encrypted end-to-end at the application layer: an X25519 key exchange derives a key used for AES-256-GCM, and matching the 6-digit SAS code out of band confirms that the endpoint public keys were not replaced, detecting a signaling service or TURN relay impersonating an endpoint. The SAS check does not prove that TURN is absent from the network path; on cross-network browser transfers, the relay still carries only ciphertext and cannot read a byte of your file. Each file is also verified with a SHA-256 hash. Same-network transfers connect straight between the two devices.

For anyone scripting transfers to a server, there's also a CLI — push/pull over SSH or daemon-direct, incremental folder sync, and send/receive by pairing code — something a LAN-only app doesn't offer. The CLI always connects directly; it never uses a relay.

When LocalSend is the better pick

If you never want to open a browser at all — say, moving files on a network with genuinely no internet access, or you just want a permanent app icon and OS share-sheet integration — LocalSend's dedicated app is the better fit. It's mature, works fully offline in the strictest sense, and its PIN mode is a nice extra layer on networks you don't fully trust.

Feature comparison at a glance

The differences that matter most, side by side:

Frequently asked questions

Do I need to install anything to use Relayium on the same network?

No. Open relayium.com in a browser on both devices while they're on the same network and they see each other automatically — no app, no account, no pairing code.

Does LocalSend need an internet connection?

No — that's one of its strengths. LocalSend works entirely over the local network with no server involved, so it keeps working even with no internet at all.

Can Relayium send files to someone on a different network?

Yes. Create a pairing code (or share the join link it generates) and the other device connects from anywhere. In the browser that cross-network connection is carried by an encrypted TURN relay by design, so it comes up in a second or two instead of waiting on direct-connection attempts that rarely succeed between two home networks; the relay forwards ciphertext and cannot read your files. Creating the code requires signing in; the person you hand it to never does.

Is Relayium open source?

Yes, AGPL-3.0-licensed, with the full protocol and code public at github.com/relayium/relayium — the same kind of openness that makes LocalSend trustworthy.

Which one is more private?

Both keep same-network transfers off a public server — on the LAN, Relayium's two devices talk directly to each other. LocalSend secures its local transport; Relayium adds an independent, application-layer encryption channel with a SAS code both sides can verify, on the LAN or across networks, which is why the relay on the cross-network path only ever sees ciphertext.

See how a same-network transfer feels with nothing to install — just open the page on both devices.

Try Relayium now

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