Duplicati — The Free NAS-to-Cloud Backup That Never Sleeps
Duplicati is open-source, runs natively on Synology/QNAP/Asustor/TerraMaster as a package, and does encrypted incremental backup to cloud drives or S3 — free, forever.
What it does
Install the Duplicati package from your NAS's package center (it is in Synology's, QNAP's, Asustor's, and TerraMaster's stores; on UGREEN/UniFi/fnOS use the community .ipk/.deb or Docker). Point it at one or more source folders, pick a cloud destination (rclone covers Drive, OneDrive, pCloud, Dropbox, S3-compatible, Backblaze B2, Azure Blob, and more), and set a schedule. Every run keeps a versioned, encrypted, compressed archive; the browser UI on the NAS handles restores and prunes.
Pricing
The core is free and open-source, forever. The optional Duplicati Cloud is a paid managed hosting tier for people who want a vendor-run archive target instead of their own cloud account. For a household that already pays for Drive or OneDrive, Duplicati is genuinely free.
Good at
- Synology/QNAP/Asustor/TerraMaster owners who want free cloud backup
- Encrypted, incremental, versioned backups to rclone-supported clouds
- Scheduled unattended backup from the NAS itself
Not for
- Windows-PC-to-cloud without a NAS
- Users who want a polished mobile app experience
Key features
- Free, open-source, native NAS package
- Encrypts and compresses, then pushes to rclone-supported cloud (Drive, OneDrive, S3, Backblaze B2, etc.)
- Scheduled, incremental, versioned — keeps 30+ previous versions by default
- Browser UI on the NAS, zero Windows box required
Frequently asked questions
Does Duplicati back up the whole NAS or just folders?
Folders and shares, not a full image. For a whole-NAS snapshot use the NAS's own tool (Hyper Backup, MyArchive, Duple Backup, HBS 3). Duplicati is the cloud copy that sits on top of a 3-2-1 plan.
Can Duplicati back up to an external USB drive attached to the NAS?
Yes — USB shares are a supported destination, so you can keep an offline USB copy on the NAS for the '1 off-site' in 3-2-1 without cloud costs.
Is Duplicati safe to leave on overnight?
Yes. It is a background service on the NAS, runs on schedule, and the cloud destination is authenticated. The browser UI is for setup and restores.
This page is part of the NAS security encyclopedia: 12-step hardening checklist, 3-2-1 backup rule, "Am I affected?" 60-second check.
Last updated: November 2026 · prices are US list prices at the time of writing. As an Amazon Associate we earn from qualifying purchases.