The Mendix Developer App is a utility for Mendix developers to test hybrid mobile apps using PhoneGap. After installing the Mendix Developer App you will be able to connect to your Mendix project by scanning the QR code. Mendix generates this code if you choose the "deploy to hybrid app" option in the Mendix Business Modeler. This allows you to instantly view and test your app on the mobile device including access to the native device APIs.