Restic is a modern backup program that can back up your files from Linux, BSD, Mac and Windows to many different storage types, including self-hosted and online services easily, being a single executable that you can run without a server or complex setup effectively, only transferring the parts that actually changed in the files you back up securely, by careful use of cryptography in every part of the process verifiably, enabling you to make sure that your files can be restored when needed freely - restic is entirely free to use and completely open source