Effectively, one way or another you'd be navigated to the website that is registered with your NFC chip as described above. If your site used the user agent header to do redirects that'd be up to you. For example, you could try and see if the user agent said it was Android OS and redirect to a page telling them to get an iPhone if they want to use your App Clip :) So it is ultimately up to you what they see. It is your site, and their web browser. I tried Core NFC out with some of the tags I bought when I got my Xs which supports background tag reading. iOS beautifully shows a local notification on the top of the screen, and then tapping opens Safari directly to my page, or presumably the universal link into my app although I didn't try that. My Android friends, the experience for them wasn't the same and varied for each of them. Some OEMs went straight to internet browser, while others prompt the user asking them what they wanted to do (choose chrome or x, y, z other browsers).