kotlin or flutter are best for app developing .

any body can more information about in this qustion ples tell and share lets discuss.

There is a post already made by someone that tells all ur answers, here it is. With kotlin multi-platform u can create apps that is native to each platform since it uses native apis and ui to build apps, u can extend ur android project to make cross platform apps and over 80-85% code is shared between all platforms, also there is jetpack compose and compose multi-platform that has beautiful dsl(s) that r made using kotlin, for making ui just like flutter. Kotlin Multi-Platform will be in beta after sometime, but can be used in production. Flutter on the other side, re-implemented a ui framework using skia graphics and a c/c++ engine, and uses native canvas apis to draw ui, thats why resulting app is almost native. Flutter is stable on android and ios, and kinda windows(recently) and is already on version 2, and almost 90-95% code is shared among platforms. IMHO, Kotlin is better because it is a preferred language for android and it really does its job perfectly with Multi-platform apps too. And u know, languages and frameworks r just tools, u just need right tool for ur job, and if there is a right tool in ur hand, everyone will be happy, including u, ur boss and ur customers.