Relayium

Relayium vs AirDrop: a cross-platform AirDrop alternative

Last updated: 2026-07-31

AirDrop is one of the best file-sharing experiences ever shipped. Between an iPhone, iPad and Mac it is fast, private, and effortlessly built into the system — Relayium does not pretend to beat it on Apple's home turf.

The catch is the boundary: AirDrop only talks to other Apple devices. This article compares the two fairly, explains where AirDrop is genuinely better, and shows where Relayium helps — sending between an iPhone and a Windows PC, an Android phone and a Mac, or a Linux laptop and an iPad, straight from the browser.

What AirDrop gets right

AirDrop uses Apple Wireless Direct Link to bring up a peer-to-peer Wi-Fi connection between two nearby devices, with Bluetooth handling discovery. The result is quick, direct, and works even when neither device is on a network — no router, no internet, no account.

It is also deeply integrated: the share sheet is one tap away in every app, transfers are encrypted, and received files land in the right place automatically. For moving photos or documents around inside an all-Apple household, it is hard to beat.

The catch: AirDrop stays inside Apple's world

AirDrop simply does not exist for Windows, Android or Linux. There is no official client and no interoperability, so the moment one side of the transfer is not an Apple device, AirDrop is not an option at all.

That is exactly the gap most people hit: an iPhone photo that needs to reach a Windows PC, an Android video going to a Mac, or files moving between a Linux workstation and an iPad. The usual workarounds — a cable, email to yourself, or a cloud upload and re-download — are slower and route your files through someone else's server.

How Relayium bridges the gap

Relayium runs entirely in a modern web browser with nothing to install, so any two devices that can open a web page can transfer to each other regardless of platform: Windows, macOS, Linux, Android and iOS all interoperate. On the same Wi-Fi, both devices open relayium.com and discover each other automatically; on different networks you connect with a short pairing code instead.

On the same network the transfer runs directly between the two devices over WebRTC. The cross-network path is deliberately different: a pairing-code room forces relay-only ICE, so the stream travels through a TURN relay and the connection comes up in a second or two instead of spending some 20 seconds on direct-candidate checks that almost never succeed between two home networks. Either way a second, independent encryption layer sits on top: an X25519 key exchange derives a key used for per-chunk AES-256-GCM, and that key never reaches any server — so the relay only ever moves ciphertext it cannot read. With advanced verification on — it is off by default — both devices show the same 6-digit verification code (a Short Authentication String). Comparing it out of band confirms that the X25519 endpoint public keys were not replaced, detecting if the signaling service or a TURN relay impersonated either endpoint. It does not prove that TURN is absent from the network path: cross-network TURN remains in the data path but carries only ciphertext. Each file is also checked end-to-end with a SHA-256 hash. You can send up to 1,000 files per batch; on the same network no account is needed, and creating a pairing code to send across networks requires signing in — the person you send to never needs an account. If the connection drops, the transfer can resume instead of restarting.

Honest limits on iPhone and iPad

This is the part to be upfront about: receiving very large files in a mobile browser is not as smooth as native AirDrop. When no streaming path applies — typically several files arriving at once in a browser without the File System Access API, which means Firefox, Safari and everything on mobile, since every iOS browser is WebKit — the incoming data is held in memory instead. Relayium warns before starting a download it estimates will need more than roughly 256 MB of memory. That number is a deliberately conservative estimate rather than a measured hard limit: a roomy desktop may sail well past it, while a phone juggling other tabs can struggle sooner.

There is more streaming available than that suggests. Chrome and Edge use the File System Access API: a single file goes through a Save As dialog straight to disk, and a whole batch streams into a folder you pick — no size ceiling, no memory pressure. Even without that API a single file can stream to disk through the service-worker download path, so Firefox and Safari are not stuck buffering across the board. That path is what the optional stored download-link mode uses — your browser encrypts the files with AES-256-GCM and the key lives only in the URL fragment, so the server holds zero-knowledge ciphertext it cannot read; creating such a link requires the sender to sign in, while a realtime transfer on the same network does not.

AirDrop vs Relayium at a glance

The differences that matter most, side by side:

Frequently asked questions

Is there an AirDrop for Windows?

No — AirDrop is exclusive to Apple devices and has no Windows client. Relayium is the cross-platform alternative: it runs in any browser, so a Windows PC can send to and receive from an iPhone or Mac just as easily as between two Apple devices.

How do I send a file from an iPhone to a Windows PC?

Open relayium.com in a browser on both devices. On the same Wi-Fi they discover each other automatically; otherwise enter the pairing code shown on one device into the other, which requires whoever creates that code to sign in. Pick up to 1,000 files — and if advanced verification is on, confirm the 6-digit verification code matches on both screens — and the transfer runs between them end-to-end encrypted — directly on the same Wi-Fi, or over a relay that only ever sees ciphertext once you have paired across networks.

Do I need to install an app?

No. Relayium is a web page — there is nothing to install on either device, on any operating system. It is free and open source under the AGPL-3.0 license at github.com/relayium/relayium, so you can audit it or run your own instance.

Send between Apple and everything else — no install, and no account needed on the same network.

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