

In addition to what others have said, Syncthing will use public relay servers if it can’t make a direct connection between your devices. Everything is encrypted, so it’s not unsafe or anything as far as i know, but if you want to run your own private Syncthing relay server, you can. (Or run your own public one)










If you have a need for Calendar or To-dos, Radicale is a nice CalDAV/CardDAV server that’s pretty tiny. For me its sitting there at idle using 35MB of RAM.