Syncthing: open-source, device-to-device sync

Moving files between multiple computers usually comes down to two options: copy them by hand with a USB drive, or upload to cloud storage and download again. The first is manual labor; the second takes the long way around and hands your data to a third party. Syncthing takes a different route: an open-source, continuous sync program written in Go that transfers files directly between your own devices, peer-to-peer, with no cloud involved at any point. GitHubDaily recommended it in March 2025.

Core features

• Continuous, automatic sync: designated folders on two or more devices stay in sync automatically in the background, needing human intervention only when necessary.
• No third-party cloud: files transfer peer-to-peer between devices, with no account system or cloud relay step, reducing the surface for interception or tampering.
• Security as the top priority: the project’s stated goals explicitly include preventing eavesdropping and unauthorized modification, and avoiding damage to users’ files.
• Cross-platform coverage: aims to cover the common computing platforms, with ready-made GUI clients for Windows, macOS, and Linux.
• Verifiable release chain: binaries are GPG-signed, automatic upgrades use built-in ECDSA signatures, and the macOS and Windows builds are additionally code-signed.

Typical use cases

• You have multiple computers (say, a desktop plus a laptop) and want a working directory to stay automatically in sync, skipping USB drives and cloud relays.
• Privately syncing photos, documents, and other personal data between your own devices without letting files land on a third-party server.
• You have a server at home or in a rack that’s always online, and want to deploy it as a persistent sync node using the official Docker image.

Quick start

1. Follow the official getting started guide to install it and complete initial device pairing.

2. To build from source, clone the repo and run this from the project root—the build output lands in ./bin:

go run build.go

3. See the repo’s README-Docker.md for Docker deployment.

Summary

This is mainly aimed at individual users: if you have multiple devices and want syncing that skips third-party clouds and keeps your data in your own hands, it’s worth trying. The project is open source under the Mozilla Public License 2.0, needs no account or API key, and continues to ship releases regularly. Two reminders: the README doesn’t list a complete supported-platform table—check docs.syncthing.net for the current list; and security issues should be reported by email to security@syncthing.net, not posted to public forums or issue trackers.