Compare software

Tarsnap vs Kopia: catalog facts
Tarsnap	Kopia
Paid Prepaid usage billing at $0.25 per GB-month stored and $0.25 per GB transferred, with no…	Free Free and open source, with no paid edition.
macOS, Linux, Command line	Windows, macOS, Linux, Command line
Client-side encryption with keys only you hold Deduplication uploads only changed data	A desktop app and a command line tool that share the same repository format End-to-end encryption with keys you control, plus compression and deduplication
Command line only, with no graphical interface No native Windows client, only Cygwin or WSL	Backs up the files and folders you choose; it is not a whole-disk imaging tool Still pre-1.0, so repository format changes between versions are possible
Downloadable app, Hosted service	Downloadable app
Closed source	Open source
License not stated	License: Apache-2.0
Account needed	No account needed
Needs internet	Works offline
Official website Full listing and sources Checked September 23, 2026	Official website Full listing and sources Checked September 20, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.