Food Delivery UI Kit in Flutter – 3 Apps – Customer App + Delivery App + Owner App UI Kit for food delivery in Flutter – 3 apps – client app + delivery app + owner app. Flutter is an open source mobile development SDK created by Google. It is used to develop Android and iOS apps, and is also the main method of making apps for Google Fuchsia. Flutter widgets include all the important platform differences such as scrolling, navigation, icons and fonts to ensure full performance on both iOS and Android.