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Kopia vs Tarsnap: catalog facts
Kopia	Tarsnap
Free Free and open source, with no paid edition.	Paid Prepaid usage billing at $0.25 per GB-month stored and $0.25 per GB transferred, with no…
Windows, macOS, Linux, Command line	macOS, Linux, Command line
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	Client-side encryption with keys only you hold Deduplication uploads only changed data
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	Command line only, with no graphical interface No native Windows client, only Cygwin or WSL
Downloadable app	Downloadable app, Hosted service
Open source	Closed source
License: Apache-2.0	License not stated
No account needed	Account needed
Works offline	Needs internet
Official website Full listing and sources Checked September 20, 2026	Official website Full listing and sources Checked September 23, 2026

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