Syncthing

About

Syncthing is a continuous file synchronization program that keeps files in sync between two or more computers in real time. Your data is stored only on your own computers, not on any central server, and you choose where it is stored, whether it is shared with any third party, and how it is transmitted over the internet. All communication is secured with TLS and uses perfect forward secrecy, and every device is identified by a strong cryptographic certificate, so only devices you have explicitly allowed can connect.

Syncthing can synchronize as many folders as you need, either with other people or just between your own devices. You configure and monitor it through a responsive browser-based interface, and it works on macOS as well as Windows, Linux, and other systems. It does not require IP addresses or advanced configuration, and it works over a local network and over the internet. Each machine is identified by an ID that you can share, and UPnP can be used instead of manual port forwarding.

Syncthing is open in several ways. Its protocol is a documented specification, its source code is available on GitHub, and bugs are publicly visible. Development and usage are open for discussion.