Backup · head to head
Duplicacy vs Kopia
Kopia
Backup
Open source deduplicating backup with client side encryption and a repository on almost any storage
- From
- Free
- Rated
- -
The short version
- Each has a real cost: Duplicacy web GUI pricing tier not specified on product page; Kopia space is only reclaimed when maintenance runs, and in a shared repository full maintenance is owned by one client, so if that machine goes away the repository grows for ever while every backup still reports success.
- They diverge on capability: Duplicacy covers Lock-free deduplication, Kopia covers Content defined chunking.
- Prices and features above were last checked on 31 August 2026.
Where they differ
Only the attributes on which Duplicacy and Kopia actually diverge.
Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Backup).
What each one covers
Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.
Only in Duplicacy
- Lock-free deduplication
- Client-side encryption
- Multiple computers
- Erasure coding
- Variable-size chunking
- RSA encryption
- AWS S3
- Azure
Only in Kopia
- Content defined chunking
- Global deduplication
- Pack blobs
- Client side encryption
- Desktop and command line
- Repository verification
What people use each for
The jobs each tool is most often brought in to do.
Duplicacy
- Client-side encrypted cloud backupsnot Kopia
- Lock-free deduplication for efficient backup storagenot Kopia
- Multi-destination backup supportnot Kopia
Kopia
- Backing up laptops and workstations to cheap object storage with a desktop interface rather than a cron jobnot Duplicacy
- Deduplicating backups of several similar machines into one repository so common content is stored oncenot Duplicacy
- Replacing a chunk based tool whose per object charges made a cheap bucket expensivenot Duplicacy
- Keeping an encrypted offsite copy where the storage provider must never be able to read the contentsnot Duplicacy
Where each one falls short
Documented limitations, not opinions. Every one is a constraint you would hit in normal use.
Duplicacy
- Web GUI pricing tier not specified on product page
Kopia
- Space is only reclaimed when maintenance runs, and in a shared repository full maintenance is owned by one client, so if that machine goes away the repository grows for ever while every backup still reports success.
- The repository format has changed across versions and mixing client versions against one repository is discouraged, so a fleet must be upgraded together rather than machine by machine.
- There is no central orchestration or reporting for many machines, so monitoring a fleet means building your own alerting around exit codes.
- Restoring many small files is slower than the backup was, because content must be reassembled from pack blobs, and this is rarely tested until the day it matters.
- Encryption is client side with no escrow, so a lost repository password means the data is unrecoverable and there is no vendor to appeal to.
Pricing, plan by plan
Duplicacy
FreeNo published plan breakdown. See the Duplicacy review.
Kopia
Free- KopiaFree
- Full functionality, no data limit
- Desktop application included
- Any supported storage back end
Which should you pick?
Choose Duplicacy if
- You need lock-free deduplication.
- You want to start without paying.
- You work on macOS, Linux, Windows.
- You also want client-side encryption.
Choose Kopia if
- You need content defined chunking.
- You want to start without paying.
- You work on Linux, macOS, Windows, Docker.
- You also want global deduplication.
Questions people ask
- Is Duplicacy or Kopia better?
- Neither clearly leads. Duplicacy starts at Free and Kopia at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
- Which is cheaper, Duplicacy or Kopia?
- Duplicacy starts at Free and Kopia at Free.
- Does Duplicacy or Kopia run on more platforms?
- Duplicacy runs on macOS, Linux, Windows. Kopia runs on Linux, macOS, Windows, Docker.
- Can I use Duplicacy for free?
- Both have a free tier, so you can try either at no cost before committing.
- What is Duplicacy best used for?
- Duplicacy is most often used for client-side encrypted cloud backups, lock-free deduplication for efficient backup storage, multi-destination backup support. Of those, client-side encrypted cloud backups and lock-free deduplication for efficient backup storage are not what Kopia is typically brought in for.
- What can Duplicacy do that Kopia cannot?
- Duplicacy covers Lock-free deduplication, Client-side encryption, Multiple computers, Erasure coding. Kopia covers Content defined chunking, Global deduplication, Pack blobs, Client side encryption.
Answered from the vendors’ own pages
Duplicacy: What is the cost of the Duplicacy command line version for commercial use?
The commercial license for Duplicacy's command line version costs $50 per machine per year. The CLI version is free for individual users.
SourceKopia: Is a partly corrupt repository still restorable?
Partly. Deduplication means one damaged pack blob affects every snapshot referencing its contents, but unaffected files still restore. Run verification regularly rather than assuming.
Duplicacy: Is pricing available for the Duplicacy Web GUI edition?
No pricing information is provided for the Web Edition (GUI) on the Duplicacy website. You would need to contact [email protected] for Web Edition pricing details.
SourceKopia: How does it compare with restic?
Similar guarantees, with packing that behaves better on per operation billing, a desktop interface, and compression enabled by default.
Duplicacy: Are volume discounts available for IT service providers?
Yes, volume discounts are available for IT service providers and resellers. Contact [email protected] to discuss volume pricing options.
SourceKopia: Do I need to run maintenance manually?
It is scheduled automatically by default, but you must ensure the client that owns full maintenance keeps running, otherwise deleted snapshots never free space.
Duplicacy: What backup modes and features are included in the free version?
The free version includes file, disk, partition, and system backup with full, incremental, and differential backup modes. It also offers scheduled backups, encryption, and emergency disk creation.
SourceKopia: Can several machines share one repository?
Yes, and that is where deduplication pays off, but they should run compatible versions and only one owns full maintenance.
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