True peer-to-peer
Files flow directly between your devices over WebRTC. Our server only helps with the introduction — your data never lives on it.
End-to-end encrypted · peer-to-peer
Sync your files
directly between your devices.
Mo-Syn is a private sync tool. Your files travel between your devices through an encrypted tunnel — they never live on our servers.
Free · No account required to try
mosyn.app
My Devices
2 online · 1 offline
All Online
MacBook Pro
peer-7c4f2a…
3
248
67%
project-final.zip
Office Desktop
peer-7c4f2a…
3
1042
100%
iPhone 15
peer-7c4f2a…
3
87
100%
Encrypted
Why Mo-Syn
Built for privacy. Designed for speed.
Six principles guide every decision.
End-to-end encrypted
Encryption keys never leave your devices. Even if our infrastructure were compromised, your files stay unreadable.
Cross-platform
Native apps for Windows and macOS, a polished web app for Linux and mobile, all sharing one identity.
Optimized transfers
Smart change-detection means only the bytes that actually changed travel across the wire.
Instant text share
Beam clipboards, snippets, and short notes between devices in milliseconds, not seconds.
Transparent design
No tracking, no telemetry, no dark patterns. Plain protocols you can audit and reason about.
How it works
Three steps to a synced fleet of devices.
- 1
Step 1
Install or open
Grab the desktop app for your computer, or open Mo-Syn in any browser to start instantly.
- 2
Step 2
Pair your devices
A single device ID is all you need to authorize a peer. Approve once, sync forever.
- 3
Step 3
Drop a folder
Drag a folder onto Mo-Syn and the same content appears on every paired device, in real time.
Get Mo-Syn
Available everywhere you work.
Pick the build that fits the device you are on. Same identity, same data, every platform.
Windows
Native installer with autostart and tray support.
Download .exemacOS
Universal binary for Apple Silicon and Intel.
Download .dmgLinux
Run as a Progressive Web App today, AppImage soon.
Open as PWAWeb
Open the app instantly in any modern browser.
Open web appFAQ
Common questions, straight answers.
Does Mo-Syn ever see my files?
No. Files are transferred directly between your paired devices, end-to-end encrypted. Our server only helps your devices find each other — it cannot read what you sync.
How is this different from Dropbox or Google Drive?
Cloud services keep a copy of your files on their servers. Mo-Syn does not. Your devices talk to each other directly, and files only exist where you explicitly placed them.
What happens if my devices are offline?
Mo-Syn waits. As soon as two paired devices come online together, they reconcile changes peer-to-peer.
Is there a file size limit?
No artificial limits. Transfer speed is bounded by your network, not by us.
How does pairing actually work?
Each device has a public ID. To pair, one device sends a request to another, which the receiving user must approve. Once approved, both devices remember each other and connect directly.
Can I use Mo-Syn for sensitive work data?
Yes — Mo-Syn was designed for it. End-to-end encryption and direct device-to-device transfers mean nothing leaks through a third party.
Mo-Syn
Reclaim your files. Today.
Set up Mo-Syn in under two minutes.