Duplicati

Duplicati is a free, open-source backup client that securely stores encrypted, compressed, and incremental backups to a wide range of cloud storage providers and remote servers — including Amazon S3, Google Drive, OneDrive, Backblaze B2, SFTP, WebDAV, and many more.

It runs as a background service with a web-based interface, allowing you to configure schedules, retention policies, and encryption without leaving your browser. All data is encrypted client-side before leaving your machine, following a true zero-knowledge (trust-no-one) model — meaning even the storage provider cannot read your files.

Compared to services like Backblaze Personal Backup or Acronis Cyber Protect, Duplicati gives you full control over where your data is stored and eliminates recurring subscription fees for backup software. It is ideal for self-hosters and privacy-conscious users who want automated, encrypted offsite backups without vendor lock-in.