AutoFwd is a free to use service for any app developer.
AutoFwd allows you to provide a short link such as www.AutoFwd.com/flappyanimal and share this link with potential new users in email, websites, posters, flyers, billboards, NFC tag, etc… When they type/scan the link into a browser it will detect which device they are on, if they are on an iOS device it will take them to AppStore, Android device goes to GooglePlay or Amazon, Windows Phone to the Windows MarketPlace.
If the app developer hasn’t released say a Windows Phone 8 version the user will see a notification that the app is not available for download yet on that platform and they are now offered the ability to receive an email when that app developer does add a WP8 version automatically!
This allows app developers to methodically track demand for various devices for their particular app and retain past potential clients as a new platform is added. It also allows app developers and marketing teams to modify the links should they ever need to point to different locations in future. E.g. a marketing poster being designed where the app isn’t yet in appstore for any direct link can be setup before the app is available.
AutoFwd will generate the QR code for you as well so you only need a single QR code to represent all downloads.
The service is free to use for all!
Give it a try here…