This application comes with an In-App Admin panel which is made in the Firebase Cloud Firestore database. That means you don't need to buy any hosting server or have to pay extra money.
You just have to create a free Firebase account and you are ready.
Flutter is an open-source mobile application development SDK created by Google. It is used to develop applications for Android and iOS, as well as being the primary method of creating applications for Google Fuchsia. Flutter widgets incorporate all critical platform differences such as scrolling, navigation, icons, and fonts to provide full native performance on both iOS and Android.