The development of the mobile application became the software organization’s fundamental backbone. For certain companies that are around the industry, it has become life and blood. And when the mobile app comes down – cross-platform is something that has to be in the picture. Business enthusiasts and creators of mobile applications reluctantly relied on two frameworks, namely-React Native and Flutter. With all mobile apps increasingly prevalent, almost every company needs a mobile app. Such applications aid in keeping the industry and consumer world competitive. FLUTTER For the Front-end app, flutter is one of the most talked-about apps for Android and iOS. When it is discussed; two conditions are possible which appear to come across. The Flutter app identifies and secures the client as if it was a website, and then preserves the view of the network into a native client. It also protects the native controls and molds with the cross-platform structure. Although flutter approaches differently from another mobile cross-platform development system when dealing with developing a device with flutter, it offers the user a lightweight runtime engine to host the application. KOTLIN Emerging as one of the most immediately embraced languages, Kotlin (supported by Google) is considered the standard language for Android App Development. The programming language, developed by JetBrains, is based on Java Virtual machine. It is remarkable for its interoperability with java and its usable parts. The codes in Kotlin are considered to be secure and trustworthy because the language overrides popular programming inconsistencies resulting in fewer device crashes and machine failures. Comparison Parameters Flutter Kotlin Performance The speed of the apps is outstanding Performs faster and is better in security, syntax, and compatibility. Language Uses Dart Uses Java and targets JVM, JavaScript, and Native. UI experience Provides with one of the best User Interface. It allows users to construct native apps and it is 100% interoperable in Java. Pricing Open Source Open Source Testing support Provides a rich set of testing feature. It operates with Firebase, which is an efficient Baas platform. Integration With both Android as well as iOS platform Provide the user with multiplatform within the native ecosystem Minimum supported platform Support Android Jelly Bean, v16, 4.1.x+ versions and iOS 8+ Operates on any of the older Android versions Conclusion Both these systems are considered to be effective for the development of both the natives and cross-platform mobile apps, and seek to minimize the time and cost of the production of the app alongside enhanced user performance. We at softieons technology work on mobile app development and help our customers in the growth of their business.