> It is surprisingly difficult to make synchronisation work between two devices that might run different hard- and firmware and even potentially software versio

> It is surprisingly difficult to make synchronisation work between two devices that might run different hard- and firmware and even potentially software versions. Cloud based APIs as middleware is soo much easier in comparison. Even if that were true (and it's not), it's not how Garmin sync works. The website isn't cloud based middleware, and the watch and phone sync over bluetooth. It really is as dumb and frustrating as the OP describes. Before syncing with the watch, over bluetooth, the app connects to the Garmin website. If the web connection fails then the transfer fails.