#KopiaLens vs Duplicacy

Duplicacy is a proprietary backup engine with a lock-free design, a CLI and a web UI, and a per-computer licence for making backups. KopiaLens is a free backup app on the Kopia engine that adds analysis and cleanup inside the repository.

	KopiaLens	Duplicacy
What it is	A backup app that shows what is inside your backups	A proprietary deduplicating backup engine with CLI and Web Edition
Backups with	Kopia repositories	Duplicacy storage, its own format
Platforms	Windows, macOS, Linux, Docker and NAS, Home Assistant, browser	Windows, macOS, Linux, FreeBSD
Scheduled backups	Yes	Yes in Web Edition, with a licence
Concurrent backups from several machines	Kopia repositories can hold several computers	Yes, lock-free by design
Browse and restore	Yes	Yes
Per-folder size after dedup	Yes	No
Reclaimable space and removal previews	Yes	No
Remove files from old snapshots	Pro, guided with previews	No; prune removes whole revisions
Price (November 2026)	Free; Pro $20/year or $50 lifetime at launch pricing	CLI free for personal use; GUI from $20 first year, $5/year after; commercial $50/computer/year; backups in Web Edition need a licence

#What KopiaLens adds

• The backup app is free. Making backups, schedules, restore, verify, maintenance and notifications do not need a licence. Pro adds the cleanup layer and smart features as they arrive.
• Where the space goes. Per-folder physical size after deduplication, reclaimable space, churn and retention simulation.
• Removal from inside old snapshots. Duplicacy prunes whole revisions; KopiaLens takes one folder out of every revision, previews the removal across snapshots and reports what it frees (Pro).
• Search across every snapshot. Find every version of a file in one view.
• Kopia's ecosystem. The repository is a standard Kopia repository, so KopiaUI and the kopia command line can open it too.

#What Duplicacy does well

• Lock-free deduplication. Several machines can back up to the same storage at once without a shared database or a lock server. It's a different design, and the reason many people choose it.
• Mature and efficient. It has been around for years, handles large storages well, and its CLI is scriptable.
• Restore and maintenance are free. Restore, check, copy and prune do not need a licence, in the CLI or the Web Edition. Only making backups needs one.
• Many backends. S3, B2, Wasabi, SFTP, WebDAV, Google Drive, OneDrive, Dropbox and more.
• A clear per-computer licence. Personal GUI $20 for the first computer in the first year, then $5/year; commercial $50/computer/year.

#Who should pick which

Pick Duplicacy for a multi-machine setup, a scripted workflow, or an existing Duplicacy storage that you do not want to move. Its licensing is clear and its engine is proven.

Pick KopiaLens for a desktop or home-server backup where you want to know why the repository is large, find an old file, or remove one folder from every snapshot.

#Switching

KopiaLens cannot read Duplicacy storage. Moving means a new Kopia repository and keeping Duplicacy installed for the old revisions until they expire. There is no conversion tool, and the old data is not re-uploaded into the new repository.

The backup app is free. Pro, for cleanup, costs $20 a year or $50 lifetime at launch pricing. Download KopiaLens or see the plans.

Prices and product facts checked November 2026. Spotted something out of date? Email support@kopialens.com and we'll fix it.