What is Phone platforms?

Phone platforms are the operating systems a maker's app runs on, and they decide which phone you can pair a device with. Every brand in this group covers the two big ones, with iOS and Android listed for each of them. In practice the app has to run without stuttering, and it must sync with the health platform you already use, so check that before buying a device for a different system. All five support the same phone types here, so your choice comes down to features and battery rather than compatibility.