Unison file synchronizer
Hacker ApprovedRanked 5 of 14 file sync apps by recommenders
Free two-way file synchronizer that keeps files in sync across computers and asks for help on conflicts. Critics warn two-way sync can wipe files and there are no mobile apps.
Free two-way file synchronizer that keeps files in sync across computers and asks for help on conflicts. Critics warn two-way sync can wipe files and there are no mobile apps.
27 people gave an opinion
- recommend it
- 24
- criticize it
- 3
- approval share
- 89%
Recommended in 11 of 13 months
- November 2025: recommended
- December 2025: recommended
- January 2026: recommended
- February 2026: recommended
- March 2026: recommended
- April 2026: recommended
- May 2026: recommended
- June 2026: not recommended
- July 2026: recommended
- August 2026: recommended
- September 2026: recommended
- October 2026: recommended
- November 2026: not recommended (month in progress)
Why it carries the badge
- 24 people recommend itNeeds 10 or more, met.
- 8 recommenders for every criticNeeds 2 to 1 or better, met.
- Recommended in 11 of 13 monthsNeeds 4 or more, met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Keeps files in sync, works well
“Git-annex, Unison, and Syncthing are much better at keeping files synchronized across devices.”
Comment from 6 Dec 2025 in “Self-hosting my photos with Immich” “sometimes "unison" works better, or sometimes "syncthing"”
Comment from 24 Sep 2026 in “Ideas on modernizing the open-source desktop” “rsync and unison works great”
Comment from 27 May 2026 in “Dropbox CEO Drew Houston to step down” - Comment from 12 Jul 2026 in “Croc: Securely transfer files and folders between two computers”
- Comment from 30 May 2026 in “Algebraic Effects for the Rest of Us”
Two-way sync asks for help
“that's two-way sync, and it always prompted to ask for help by design”
Comment from 14 Apr 2026 in “Backblaze has stopped backing up your data” “it always prompted to ask for help by design”
Comment from 14 Apr 2026 in “Backblaze has stopped backing up your data”
What people warn about
Each mark is one comment
No mobile apps
“it is a blast from the past written in ocaml and there is no Android app”
Comment from 3 Nov 2025 in “Why Nextcloud feels slow to use” “Unfortunately it has no mobile apps, though.”
Comment from 3 Nov 2025 in “Why Nextcloud feels slow to use” Hard to understand for newcomers
“Unison: Language server failed to connect, is there a UCM running?”
Comment from 26 Nov 2025 in “Unison 1.0” “which is a head of the time but... not so many people understand it”
Comment from 6 Oct 2026 in “Friendship ended with Deno, now Node is my best friend”
Other file sync apps people recommend
The four most recommended other file sync apps, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
See all 14 file sync apps, rankedWhat people said
25 of the 32 comments that mention it, newest first. Each links to the original comment.
“which is a head of the time but... not so many people understand it”
“sometimes "unison" works better, or sometimes "syncthing"”
“afaict it just works for me”
“I highly recommend Unison”
“rsync and unison works great”
“that's two-way sync, and it always prompted to ask for help by design”
“it always prompted to ask for help by design”
“Unison goes a little further, which is neat but I think they're struggling getting adoption because of that”
“an interesting recent experiment”
“The two way sync is great but also a bit scary since it can wipe files.”
“It's a great piece of software (multiplatform, and it even has a GUI).”
“I've talked to people who've had good results with Haskell and even Unison”
“Git-annex, Unison, and Syncthing are much better at keeping files synchronized across devices.”
“they _can't_ send arbitrary code and data around like Unison can”
“fond memories of the web back in the early 2000s”
“I like unison but it isn't super well suited to the 'background sync' workflow.”
“I can't tell what I'm looking at as a lifelong C/Java/etc. tier programmer.”
“Unison: Language server failed to connect, is there a UCM running?”
“seriously one of the best things about it”
“I'm also excited about using this specifically for games.”
“Overall I think Unison would be a nice implementation language for really anything that needs to make interesting use of hashing, since it's just there and always available.”
“Erlang is great and was one inspiration for Unison.”
“synchronization between 32- and 64-bit platforms or even binaries compiled with different versions of OCaml was not possible”
“Unfortunately it has no mobile apps, though.”
“it is a blast from the past written in ocaml and there is no Android app”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.