What's more difficult, web or mobile app development?

[KinexMedia]

People usually ask us about web application development that is it more difficult than mobile application counterpart for the following reasons.

A typical end to end web developer needs to know HTML, CSS, JavaScript, SQL, and some backend server-side framework like Django, Ruby on Rails, J2EE, .Net. While the mobile developer needs to know primarily Objective-C or Java.

With those languages in hand the web developer will have to know lot of about the different behaviors across the many popular browsers like Firefox, IE, Chrome, and Safari including versions at least five years old.

The web developer will have to be able to write highly scalable code that handles many concurrently users. Performance bottlenecks can effect the responsiveness of the website because all of the clients are sharing the same infrastructure. For mobile applications much of the code runs on the phone and does not affect the performance of other users.

[kmartin]

I think the answer has two angles: required functionality, and development technology stack skills needed.

Talking about web development, in addition to diversity of languages and frameworks, assuming a framework-supported development strategy, complexity in functionality could be measured by proximity of required features to a framework-friendly implementation. The more you need to customize, the more complex developing becomes.

In the mobile arena, I suppose the question is considering a native-only development strategy. In that context, the technology stack is less diversified: iOS and Android both for example offer a language - Java and Swift (Apple encourages developers to use it) -, one main approach (Layouts+Activities+Intents for Android and MVC for iOS), a set of APIs and project organisation you need to learn in order to take advantage of functionality each platform is able to offer.