Duplicati is free, open-source software for backing up personal files, photos and documents in encrypted, incremental form. Backups go to local drives, a NAS or a cloud service such as Backblaze B2, Amazon S3, Dropbox, OneDrive, Google Drive, SFTP or WebDAV. Data is encrypted on your own computer with AES-256 or GPG before it is sent, and only changed parts are uploaded again. Duplicati runs on Windows, macOS and Linux and has a graphical user interface. The source code is available on GitHub under the MIT licence.
The project is developed by Duplicati Inc., a US company incorporated in Delaware in March 2024. According to the company, the client stays open source, while paid features target businesses. Because you choose the storage destination yourself, you also decide in which country your backups are stored: a European provider or your own drive keeps the data in Europe. As encryption happens locally, the storage provider cannot read the content.