Alternatives to Unison
Open source bidirectional file synchronizer for Unix and Windows
Unison ranks #6 of 11 in File sync, with an Alt Score of 81. It is licensed under GPL-3.0, free from Free and available on Windows, macOS and Linux. 12 of 12 checklist rows are verified against a public source.
Unison is a free, open-source, cross-platform file synchronization tool that runs on Linux, macOS and Windows. Unlike rsync, it performs true two-way sync, detects conflicts when both replicas changed, and lets the user resolve them; it can sync over direct sockets or SSH tunnels. It remains actively maintained on GitHub, with releases as recent as May 2026.
Unison is aimed at technical users, sysadmins, and developers who want to keep two file replicas (e.g. a laptop and a server, or two machines on different platforms) in sync from the command line or a simple GUI, without relying on a third-party cloud service.
Unison performs two-way, bidirectional synchronization between a pair of replicas: it detects updates on both sides, propagates non-conflicting changes automatically, and surfaces conflicting changes for manual resolution. It supports selective synchronization of specific paths, ignore patterns for excluded files, configurable file-versioning/backups, and a compression protocol similar to rsync for efficient transfer of changed data.
Unison runs as a command-line (or simple GUI) program on both replicas and connects them either via an ssh remote-shell tunnel or via a TCP/Unix-domain socket daemon (started with 'unison -socket'), requiring no kernel modifications or superuser privileges on either host. It maintains a private archive of prior synchronization state on each host to determine what changed since the last run, then updates each replica to reflect the other's non-conflicting changes.
Where Unison stands out
Verified capabilities most alternatives don't have.
Why people leave Unison
Dashed reasons are sourced facts; the rest are opinions. Vendors can dispute.
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Ranked alternatives
Ordered by Alt Score. Click any score to see the breakdown.
GoodSync is proprietary file synchronization and backup software from Siber Systems for Windows, Mac, Linux, iOS and Android.
SyncBackPro, made by 2BrightSparks, is Windows backup/sync software used by individuals, small businesses and organizations including law enforcement and healthcare.
Syncovery, from Super Flexible Software, is a Windows/Mac/Linux sync and backup tool supporting two-way sync, versioning, encryption, and dozens of cloud/FTP/SFTP/WebDAV targets.
ChronoSync, by Econ Technologies, is a macOS application for incremental and bidirectional file/folder synchronization, bootable backups, and drive cloning, with support for SFTP, network shares and c.
FolderSync is a sync client (Android app plus Windows/Mac/Linux desktop companion) that keeps device folders synchronized with 20+ cloud providers and protocols including S3, WebDAV, FTP/SFTP, SMB and.
Feature comparison
Rows come from the File sync checklist (16 rows). Human-verified cells only. ? means the value has not been verified.
| File sync checklist | Unison | GoodSync | Seafile | SyncBackPro | Syncthing | Syncovery |
|---|---|---|---|---|---|---|
| Pricing model | ||||||
| Starts at | ||||||
| License | ||||||
| Platforms | ||||||
| Peer-to-peer (no server) | ||||||
| Self-hostable server | ||||||
| Selective sync | ||||||
| Delta sync | ||||||
| Conflict handling | ||||||
| Untrusted-device encryption | ||||||
| Bandwidth limits | ||||||
| LAN sync | ||||||
| File versioning | ||||||
| Ignore patterns | ||||||
| Mobile support | ||||||
| Open source |
Every fact and feature listed for Unison is verified against its own pages. Each alternative is sourced on its own page.
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Pricing model Free verified 2026-07-30
No paid tier exists; project is free open-source software with no commercial offering.
Unison is Free; full source code is available under the GNU Public License, Version 3.
https://github.com/bcpierce00/unison/blob/master/README.md -
Platforms Windows, macOS, Linux verified 2026-07-30
CI also builds for other Unix-like systems (FreeBSD, OpenBSD, NetBSD via pkgsrc) per the same page; only Windows/macOS/Linux map to the checklist vocabulary.
Ubuntu is probably 20.04... macOS is built on macOS 10.15 with a target of 10.6... Windows is built with mingw, and will likely work on Windows 7 and up.
https://github.com/bcpierce00/unison/wiki/Obtaining-Unison-Sources-and-Binaries -
License GPL-3.0 verified 2026-07-30
GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007
https://github.com/bcpierce00/unison/blob/master/LICENSE -
Starts at Free verified 2026-07-30
Unison is Free; full source code is available under the GNU Public License, Version 3.
https://github.com/bcpierce00/unison/blob/master/README.md -
Status active verified 2026-07-30
Latest tagged release v2.54.0 published 2026-05-01; latest commit to master was 2026-07-23, one week before this research date.
v2.54.0 ... 2026-05-01T00:33:56Z
https://github.com/bcpierce00/unison/releases -
Peer-to-peer (no server) Yes verified 2026-07-30
Unison works between any pair of machines connected to the internet, typically communicating over ssh, but also directly over TCP.
https://github.com/bcpierce00/unison/blob/master/README.md -
Self-hostable server Yes verified 2026-08-11https://raw.githubusercontent.com/bcpierce00/unison/master/doc/unison-manual.tex
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Selective sync Yes verified 2026-08-11https://raw.githubusercontent.com/bcpierce00/unison/master/doc/unison-manual.tex
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Delta sync Yes verified 2026-08-11https://raw.githubusercontent.com/bcpierce00/unison/master/doc/unison-manual.tex
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Conflict handling Yes verified 2026-08-11https://raw.githubusercontent.com/bcpierce00/unison/master/doc/unison-manual.tex
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Untrusted-device encryption No verified 2026-08-11https://raw.githubusercontent.com/bcpierce00/unison/master/doc/unison-manual.tex
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Bandwidth limits Partial verified 2026-07-30
This is the maxthreads concurrency preference, an indirect throttle, not a literal KB/s bandwidth cap.
when Unison is used over a low-bandwidth link it may be helpful to set it lower (e.g. to 1) so that Unison doesn't soak up all the available bandwidth
https://raw.githubusercontent.com/bcpierce00/unison/documentation/unison-manual.txt -
LAN sync Yes verified 2026-08-11https://raw.githubusercontent.com/bcpierce00/unison/master/doc/unison-manual.tex
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File versioning Yes verified 2026-08-11https://raw.githubusercontent.com/bcpierce00/unison/master/doc/unison-manual.tex
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Ignore patterns Yes verified 2026-08-11https://raw.githubusercontent.com/bcpierce00/unison/master/doc/unison-manual.tex
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Mobile support No verified 2026-07-30
Enumerated CI platforms are Ubuntu, macOS, and Windows only; no iOS/Android binaries or apps are mentioned anywhere in the project's wiki or README.
Note that there are no binaries for most operating systems, and no binaries for most CPU architectures. Binaries are limited to a small number of OS/CPU combinations, based on what github offers.
https://github.com/bcpierce00/unison/wiki/Obtaining-Unison-Sources-and-Binaries -
Open source Yes verified 2026-07-30
Unison is Free; full source code is available under the GNU Public License, Version 3.
https://github.com/bcpierce00/unison/blob/master/README.md
FAQ
Yes. GoodSync, Syncthing and rclone have a free tier or are fully free. Free-tier limits in the comparison table are verified and dated.
Seafile, Syncthing and rclone — every license claim links its source.