I think both Android and iOS have been shipping a built in QR code scanner for some years now.
Wechat had 1.17 billion users last year and has had a QR scanner built in for many years now. Given that you need the app to login to their web or desktop applications, it can be presumed that that many users have the app installed, possibly making WeChat the most popular QR code scanner app.
Wechat had 1.17 billion users last year and has had a QR scanner built in for many years now. Given that you need the app to login to their web or desktop applications, it can be presumed that that many users have the app installed, possibly making WeChat the most popular QR code scanner app.