restic

restic is an open-source and free to use backup program that supports the three major operating systems (Linux, macOS, Windows) and a few smaller ones (FreeBSD, OpenBSD). It can back up files from Linux, BSD, Mac and Windows, to many different storage types, including self-hosted and online services.

Advantages include:

• ease of use - being a single executable that can run without a server or complex setup
• effectiveness - only transfers the parts that actually changed in the files that are backed up
• security - with careful use of cryptography in every part of the process
• verifiably - ensures that files can be restored when needed
• freely - restic is entirely free to use and completely open source