Google Flutter is a user interface (UI) toolkit that promises to do exactly that, giving you a way to develop UIs for Android and iOS from a single codebase.

This article explores the top 10 Flutter apps making waves in 2025, and walks you through how to implement in-app purchases (IAP) using Flutter.

Flutter lets you build compiled, cross-platform mobile, desktop, and web applications from a single codebase. Get started with Flutter and its easy-to-use programming language, Dart.