KnobKwest is an app that allows users to find the perfect doorknob for their door. The app offers two options - users can take a photo of their door and the app will recommend matching knob models and where to purchase them, or users can search directly for a specific knob model. KnobKwest makes money through ads on the app and by marking up prices slightly for knobs ordered through the app. It is available for free download on iOS, Android and Google Play.