Unison review (2026): is it any good?
Open-source two-way file synchronizer for Unix, macOS and Windows
Unison report card
Good · out of 4.0 · graded Nov 13, 2026
Best for two-way file sync, free and open source
Unison is a free open-source program that keeps two copies of a folder in step, on Mac, Windows and Linux, over ssh or TCP. It flags conflicts instead of picking a winner, but you get source code, the maintainers say few people work on it, and it is run from a terminal.
Who Unison is for
- Fits if you are happy in a terminal and want conflict-aware sync between two machines
- Works for people syncing a laptop with a Unix server over ssh
Who Unison is not for
- Skip it if you want a point-and-click app, as it is run from the command line
- Watch out: the project releases source, and pre-built binaries come from other sources
- Tight if you need help: the README says not to ask in GitHub issues
- Watch out: the maintainers say very few people work on it, so fixes are slow
- Not for you if you want cloud storage sync, as it is two-folder sync
Why Unison gets a 2.6
Five grades, each with its reason. The GPA is their average: an A is 4 points, an F is none.
- AValue for moneyFree under the GPL-3.0 licence, with no paid editions. Anyone can download and run it.
- AFree plan and trialThe whole program is free with no limits, and you only need the two places to sync.
- CFeaturesTwo-way sync, conflict detection, rsync-style transfers and repeat mode. It does that one job fully, and it is a smaller job: no cloud services or mobile.
- DEase of useA command-line program released as source, with pre-built binaries from packaging systems. Help comes from a wiki and mailing lists.
- CPlatforms and integrationsA program for computers alone: Mac, Windows and Linux. No phone, web or cloud integrations are listed.
What these grades rest on. Graded from this listing, whose facts were read from Unison's own pages on 13 November 2026. Not based on using the product, and shorter than our full reviews. How we review and grade.
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<a href="https://toolgpa.com/tools/unison#review"><img src="https://toolgpa.com/badge/unison.svg" alt="Unison: 2.6 GPA on ToolGPA" width="196" height="56"></a>Where Unison stands among file storage and sync services
Unison's GPA of 2.6 is higher than 62 of the 91 other file storage and sync services we grade, and level with 10.
It stands best on free plan and trial (A, above 86 of 91) and worst on ease of use (D, above 0).
Unison has no paid plan.
On features, ease of use and platforms it scores 1.7 out of 4. Nothing scores higher for less, though at least one tool matches that score at a lower price.
Each grade against the category
Every bar is all 92 file storage and sync services we grade, cut by the letter each got. Unison’s own letter is outlined.
- AValue for moneyAbove 74 of 91, level with 17
- AFree plan and trialAbove 86 of 91, level with 5
- CFeaturesAbove 2 of 91, level with 67
- DEase of useAbove 0 of 91, level with 21
- CPlatforms and integrationsAbove 1 of 91, level with 29
Price against what you get
Each dot is one of 66 file storage and sync services. Further left costs less, and higher up scores better on features, ease of use and platforms. Point at a dot to see which tool it is.
Features, ease of use and platforms, averaged
What paid plans start at, a month (each step along is roughly double) →
- The best score at each price
- Has a free plan
- No free plan
Keep Unison, or make your own?
Keep it
Unison is free, so making your own would save you nothing.
And it is not the kind of software a weekend replaces. It is one of the better ones too: its GPA of 2.6 is higher than 62 of the 91 other file storage and sync services we grade.
What you could not
- Files kept in step across devices without losing one.
- Apps for macOS, Windows and Linux that stay in step with each other.
What this rests on. Unison’s listing: what it does, where it runs, what it plugs into and what it costs. It is a judgement about the kind of software this is. We have not built a replacement for it, and making your own means looking after it too. How we decide, and every tool’s verdict.
What is Unison?
Unison is a free file-synchronization tool that keeps two copies of a folder tree up to date when both are edited separately. It runs between hosts, usually over ssh, and flags conflicting changes instead of overwriting them. It is distributed as source code under the GNU General Public License, version 3.
Worth knowing
- The project releases source code; pre-built binaries come from packaging systems or CI builds.
- The README says not to ask for help in GitHub issues; questions go to the wiki and mailing lists.
- The maintainers say very few people work on it, so bug and feature handling is slow.
- The old project website is archival; development and issues are on GitHub.
Key features
- Two-way synchronization
- Changes made on either replica are propagated to the other, and updates that do not conflict are applied automatically.
- Conflict detection
- When both sides changed the same file, Unison shows the conflict instead of silently picking a winner.
- Cross-platform pairs
- It can synchronize a Windows laptop with a Unix server, for example, over ssh or directly over TCP.
- Efficient transfers
- Small edits to large files use a compression protocol similar to rsync's, which suits slow links.
- Repeat mode
- With a filesystem monitor, repeat mode propagates changes soon after they happen.
- No special privileges
- It is a user-level program: no kernel changes, superuser rights or FUSE are needed on either host.
Unison pricing
As of Nov 13, 2026, Unison is free to use.
- Starts at
- Free
- Free plan
- None
- Free trial
- None listed
| Plan | Price | What you get |
|---|---|---|
| Free | $0 | Full source code under the GNU General Public License, version 3; there are no paid editions. |
Read from github.com on Nov 13, 2026. Prices change, so confirm with Unison before you buy.
Unison alternatives
- Unison vs Rclone
Free
- Unison vs FreeFileSync
Free plan · from €20/yr
- Unison vs Syncovery
Free trial · from $39.90 one-time
Common questions
Does Unison have an Android app?
No Android app was listed when its pages were read on Nov 13, 2026. Unison is listed for macOS, Windows and Linux.
Does Unison have an iPhone app?
No iPhone app was listed when its pages were read on Nov 13, 2026. Unison is listed for macOS, Windows and Linux.
Is Unison open source?
Yes. Unison is open source, according to its own site.
Does Unison work offline?
Yes, according to its own site. What works without a connection differs by plan and platform, so check the vendor's page for the detail.
Sources for this page
The prices, plans, platforms and features above were read from these pages on Nov 13, 2026.