Last updated: 2026-07-03
Getting a file from your laptop onto your phone should not mean hunting for the right cable, emailing yourself, or uploading to a cloud drive and downloading it again. Relayium moves the bytes straight from your computer to your phone over your own Wi-Fi, in the browser, with nothing to install on either side.
This guide walks through the wireless way step by step — same network or across networks — then compares it honestly with the usual alternatives (USB, Bluetooth, chat apps and email) so you can pick the right tool for the job.
This is the fastest path: both devices are on the same network, so they connect directly and the transfer is bounded only by your Wi-Fi. You need nothing but a browser on each device.
Your phone is on mobile data and your PC is on home Wi-Fi? That is fine — Relayium is built to reach across networks, not only the same one.
Instead of automatic discovery, the sender gets a short pairing code (or a share link). Enter the code on the other device and the two connect directly, peer-to-peer, whenever the networks allow it. When a direct path is impossible, the encrypted stream falls back to a TURN relay — the relay only ever sees ciphertext, so the transfer stays end-to-end encrypted. If the connection drops mid-way, the transfer can resume instead of starting over.
Relayium is a website, so there is genuinely nothing to install. But if you send files often, you can add it to your home screen or desktop as a Progressive Web App: it then opens in its own window and launches like a native app, while still being just the web page under the hood.
On the phone, use your browser's "Add to Home Screen" option; on the computer, use the install icon in the address bar. It stays free either way — Relayium is open source under the MIT license at github.com/relayium/relayium, and works on Windows, macOS, Linux, Android and iOS.
Because a realtime transfer never parks your files on a server, there is no upload quota to worry about. The practical limit is which browser is receiving.
In Chrome or Edge, incoming data streams straight to disk, so there is effectively no size cap — multi-gigabyte videos are fine. Firefox and Safari buffer the file in memory instead, so on those keep a single file under roughly 200 MB. If you need to send something large to a Safari-based iPhone, receiving on a Chrome-based device avoids the limit entirely.
Wireless in the browser is not the only option, and the honest answer is that each alternative has its place. Here is how the common ones compare:
Yes. Relayium runs in the browser on Windows, macOS, Linux, Android and iOS, so any combination works — Windows to Android, Mac to iPhone, Linux to a phone, and back the other way. There is nothing to install on either device.
On the same Wi-Fi the two devices connect directly, so speed is bounded by your local network rather than by any server — usually as fast as your Wi-Fi allows. Across different networks it depends on both internet connections, and Relayium falls back to an encrypted relay only when a direct link is not possible.
Yes. On top of the browser's transport encryption, Relayium adds its own layer: an X25519 key exchange derives a key used for per-chunk AES-256-GCM, and that key never touches a server. Both devices show the same 6-digit code (SAS) so you can confirm no one is in the middle, and each file is verified end-to-end with a SHA-256 hash.
Open Relayium on your computer and your phone and send your first file wirelessly — no cable, no install, no account needed.
Try Relayium now