Syncthing

syncthing/syncthingReviewed by AI

What it does

Syncthing copies changes in the folders you choose between two or more of your devices as they happen, so the same files are on each one. Files travel straight from device to device, encrypted, without being stored on a company's server. It is for anyone who wants Dropbox-style syncing without cloud storage or a subscription; it is not a backup, because there is no online copy. You run a small program on each device and manage it in your web browser. Ready downloads exist for Windows, macOS and Linux (the Windows one is a 14 MB zip).

How easy it is to install

B · installer plus one simple step · Windows

Windows B
macOS B
Linux B

On Windows the release is a ready program in a zip (syncthing-windows-amd64-v2.1.7.zip, about 14 MB) that you unzip and run, and then you pair devices by exchanging device IDs in the browser page; macOS is a zip with the same program and Linux also has .deb packages, so all three need that same pairing step and some extra setup to start with the system.

Numbers on GitHub

Stars: 89,951on Oct 31, 2026
Downloads: 111,943,08860,438 this week
Growth: +205stars in 6 days

Stars over time

Facts

Runs on: Windows, macOS, Linux
You need to install: Nothing extra
To build from source: Docker, Go
Disk space: 14 MB–41 MB · from the installer
Accounts or keys: None
Cost: Free
License: MPL-2.0 (Copyleft)
Can replace: Dropbox, Sync, iCloud Photos
Last update: Oct 27, 2026

Risk signals (3)

Infolistens on network ports
Dockerfile: "EXPOSE 8384 22000/tcp 22000/udp 21027/udp" — the program opens a web page for settings and network ports to talk to your other devices, which may need router or firewall permission.
AI review
Infobuilt in auto upgrade
README.md: "There is also a built-in automatic upgrade mechanism (disabled in some distribution channels) which uses a compiled in ECDSA signature." The program can download and install new versions of itself.
AI review
Infosigned releases
README.md: "Release binaries are GPG signed with the key available from https://syncthing.net/security/ ... macOS and Windows binaries are also code-signed."
AI review

Evidence is shown in its original language.

What Radar could not check

How it behaves on Windows when files are open or locked by other programs during sync.
Whether conflicts are handled the way you expect when the same file changes on two devices.
Whether your router or firewall lets the devices find each other without manual changes.
How the separate community helper apps that add a Windows or Mac interface work; they are not part of this repository.