Relayium vs Snapdrop & PairDrop: which secure P2P file transfer?
Last updated: 2026-07-31
Snapdrop and its actively maintained fork PairDrop are pioneers of browser-based, install-free file sharing. They are polished, familiar, and genuinely good tools — Relayium builds on the same idea rather than dismissing it.
This article compares the three fairly: what they share, where Snapdrop and PairDrop are stronger, and where Relayium is different. The short version is that Relayium's focus is encryption strength and reaching across networks, not replacing what already works well on your LAN.
What they have in common
All three run entirely in a modern web browser with nothing to install. On the same LAN, all three use WebRTC to move file bytes directly between two devices instead of parking them on a server.
On the same local network they can discover nearby devices automatically, so sending a photo from a laptop to a phone in the same room is a couple of taps in any of them.
Where Snapdrop and PairDrop shine
Snapdrop has been around for years and has a large, trusting community; PairDrop extends it with features Relayium does not try to match today.
- PairDrop adds rooms and persistent device pairing, so you can connect specific devices even across different networks by pairing code.
- Both are simple to self-host — the server code is small and well understood, which matters if you want to run your own instance.
- Years of real-world use mean broad device coverage, plenty of documentation, and a mature, predictable experience.
Where Relayium differs: application-layer end-to-end encryption
Plain WebRTC is encrypted in transit by DTLS, and that is real protection against a passive network eavesdropper. But the DTLS fingerprints that authenticate each side are exchanged through the signaling server. A malicious or compromised signaling server can substitute its own fingerprints and sit invisibly in the middle — a classic man-in-the-middle attack that DTLS alone does not stop.
Relayium adds a second, independent encryption layer on top of the WebRTC channel: an X25519 key exchange derives a key used for per-chunk AES-256-GCM, and that key is never sent to any server. To detect a man-in-the-middle, turn on advanced verification (off by default) and both devices display the same 6-digit Short Authentication String (SAS); if the codes match, no server has impersonated either endpoint or terminated the application-layer encryption. Each file is also verified end-to-end with a SHA-256 hash.
Beyond the LAN
Relayium is designed to work across networks, not only on the same Wi-Fi. Browser transfers connect directly on the same LAN; a cross-network pairing-code session uses a TURN relay by design while remaining end-to-end encrypted from browser to browser.
Across networks the TURN relay carries only ciphertext that it cannot read or decrypt, and Relayium keeps no server-side copy or history of the realtime content. There is also an optional stored download-link mode: your browser encrypts the files with AES-256-GCM and the decryption key lives only in the URL fragment, so the server stores zero-knowledge ciphertext it cannot read. On the same network, no account is needed; creating a cross-network pairing code requires the creator to sign in, while the person joining never needs an account. Creating a stored download link also requires sign-in. Transfers that drop mid-way can resume instead of restarting.
Feature comparison at a glance
The differences that matter most, side by side:
- Encryption layer: plain WebRTC relies on DTLS alone; Relayium adds application-layer X25519 + AES-256-GCM on top.
- MITM defense: Relayium offers an optional 6-digit SAS code (advanced verification, off by default) that both sides can verify; plain WebRTC has no equivalent check against a malicious signaling server.
- Across networks: Relayium connects by pairing code (or the join link it generates) over an encrypted TURN relay; LAN discovery is the primary path for Snapdrop.
- Storage mode: Relayium offers optional zero-knowledge stored download links; the others are realtime-only.
- Resume: Relayium can resume an interrupted transfer instead of starting over.
- Batch: Relayium sends up to 1,000 files per batch with a per-file SHA-256 integrity check.
Frequently asked questions
Can Relayium and Snapdrop/PairDrop replace each other?
For quick sharing between devices on the same network, any of them works well. If you need to reach across different networks or you want an extra, server-independent encryption layer with a verification code, Relayium is aimed at that; if you love PairDrop's rooms and persistent pairing, it remains an excellent choice.
Is Relayium open source and self-hostable?
Yes. Relayium is AGPL-3.0-licensed and the full protocol and code are public at github.com/relayium/relayium, so you can audit it or run your own instance — the same openness that made Snapdrop and PairDrop trusted.
Is there a performance difference?
On the same LAN, all three use a direct WebRTC path and performance is usually similar. Across networks, Relayium uses TURN by design, so relay location and capacity can affect latency and throughput. Its extra AES-256-GCM layer runs in the browser and normally adds little overhead compared with the network path.
See how the application-layer encryption feels in practice — no install, and no account needed on the same network.
Try Relayium now