Mobile app development is the process of creating software applications that run on mobile devices, such as smartphones and tablets. These apps can be built for specific platforms (like iOS or Android) or cross-platform, meaning they can run on multiple types of devices.

iOS: Swift, Objective-C Android: Kotlin, Java Cross-Platform: JavaScript, Dart, C# (for frameworks like React Native, Flutter, and Xamarin)

Cross-platform app development allows you to build apps that can run on multiple platforms (iOS, Android, and sometimes Windows) from a single codebase. This reduces development time and costs. Popular frameworks for cross-platform development include React Native, Flutter, and Xamarin.

Frontend: The user interface of the app, which users interact with. It includes the design, layout, and overall user experience. Backend: The server side of the app, which manages data and business logic. It includes servers, databases, and APIs that allow the frontend to communicate with the database and other backend services.