I use this on my Macs — I think it works on all platforms? My use case is quite interesting. I have two Nintendo Switch emulators, one on a Mac and one on a MacBook. Due to the way Nintendo handles save files, it's not the same folder name from machine to machine. You'd think it would be something dumb like \saves{serial-of-game} but no, it's weird, it's dumb, and it makes syncing a challenge.

SyncThing isn't easy to set up, but it's doable. I had to find the folder on both systems (different names, of course) and I have ST set up to where if it detects a change in one, it updates the other.

For the test, I set up Animal Crossing on the Mac, played until I could generate a save (roughly 10-15 minutes, I think: you do character creation, then a tutorial, before you're allowed to go to sleep, and wake up with real-time enabled), then I booted it up on the MacBook and expected the save to load. I got a screen (within the game) I had never seen before, something about transferring my data to a new Switch (I'm guessing there's a hardware ID in there), but then, it worked. I might have to face that screen every time, but I did what Ninten-don't — I have an Animal Crossing save that lives on two machines at once. (And I never play it. I really just did it to see if I could. I play the game on my actual Switch, the actual game I paid for, because I wasn't trying to rip off Nintendo, really, just see if I could do it. And, ST was the tool I used to accomplish it.)

SyncThing is probably my most used bit of software after LibreWolf. I have it installed on all of the computers I use so I have damn near instant, magical access to a bunch of files. It's how I sync my photos from my Pixel.

It's funny, because SyncThing is basically the reason I barely use my iPad these days. While there is a way to make it work with iOS, it's irritating enough that I just don't bother, and I don't use iCloud storage anymore, so it's a pain in the arse getting documents to it compared to just dropping them in a ST folder that my phone can access.