Syncthing keeps folders the same across computers you own. The devices talk to each other, encrypted, with no account and no company in the middle. It is open source. You approve each device. After that, changes flow.
A delete flows too. Syncthing is not a backup. If ransomware encrypts the folder on one machine, the others can receive the damage. Turn on file versioning if you use it for anything you would cry about, and keep a real backup that is not in the sync set. Relays help devices find each other. The data is still between your machines, not stored as a drive in someone else’s cloud.
Use it to skip Dropbox between your own computers. Pair it with Borg, Restic, or Kopia. syncthing.net
Turn on Syncthing’s staggered versioning or a trash-can folder before you sync anything with family. A delete on a phone, including a gallery cleaner app, will propagate. Ignore patterns should skip node_modules and disk images or you will fill every laptop. Relays and global discovery can be turned down if both machines are always on the same network. Read the device ID out loud when you pair. A wrong device is a stranger with your folder.
