# Unison review (2026): is it any good? > Open-source two-way file synchronizer for Unix, macOS and Windows Checked Nov 13, 2026 ยท graded Nov 13, 2026 by ToolGPA. 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. - **Category:** File Storage & Sync - **Made by:** Unison open-source project - **Website:** https://www.cis.upenn.edu/~bcpierce/unison - **Runs on:** macOS, Windows, Linux - **Who should skip it:** Skip it if you want a point-and-click app, as it is run from the command line. - **Facts last checked:** Nov 13, 2026 ## Pricing As of Nov 13, 2026, Unison is free to use. - **Pricing model:** 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 https://github.com/bcpierce00/unison on Nov 13, 2026. Prices change, so confirm with Unison before buying. ## 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. ## Good for - Keeping a laptop and a home or remote server in step over ssh - People comfortable with command-line tools and config files - Syncing without a cloud account or any subscription ## 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. ## ToolGPA grades **GPA: 2.6 out of 4**, graded Nov 13, 2026. 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. - **Value for money: A.** Free under the GPL-3.0 licence, with no paid editions. Anyone can download and run it. - **Free plan and trial: A.** The whole program is free with no limits, and you only need the two places to sync. - **Features: C.** Two-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. - **Ease of use: D.** A command-line program released as source, with pre-built binaries from packaging systems. Help comes from a wiki and mailing lists. - **Platforms and integrations: C.** A program for computers alone: Mac, Windows and Linux. No phone, web or cloud integrations are listed. These are ToolGPA's own grades. 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. ## Where it 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. The category's chart of price against score: https://toolgpa.com/charts/file-storage ## Keep it, 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. - You could not: Files kept in step across devices without losing one. - You could not: Apps for macOS, Windows and Linux that stay in step with each other. A judgement by ToolGPA from this listing, by rules that are the same for every tool. Nothing was built to test it. **Tags:** Open source, File sync, Works offline ## Alternatives - [Syncthing](https://toolgpa.com/tools/syncthing): Free, open source file sync directly between your own devices. [Compare](https://toolgpa.com/compare/syncthing-vs-unison) - [Rclone](https://toolgpa.com/tools/rclone): Command-line tool for syncing and mounting cloud storage. [Compare](https://toolgpa.com/compare/rclone-vs-unison) - [FreeFileSync](https://toolgpa.com/tools/freefilesync): Open-source folder comparison and sync for desktops. [Compare](https://toolgpa.com/compare/freefilesync-vs-unison) - [Syncovery](https://toolgpa.com/tools/syncovery): One-time-license file sync and backup for desktops and NAS. [Compare](https://toolgpa.com/compare/syncovery-vs-unison) ## Sources The prices, plans, platforms and features above were read from these pages on Nov 13, 2026: - https://www.cis.upenn.edu/~bcpierce/unison/ - https://github.com/bcpierce00/unison - https://raw.githubusercontent.com/bcpierce00/unison/master/README.md - https://raw.githubusercontent.com/bcpierce00/unison/master/INSTALL.md Page: https://toolgpa.com/tools/unison Listed by ToolGPA (toolgpa.com).