Languages Java – The mobile cross-platform language par excellence, you really cant go wrong by using this for apps compatible almost anywhere. C++ – A lower language than Java, and an extremely useful one at that – it is basically ubiquitous. Not the first recommendation because it often puts extra strain on a mobiles resources. C# – The Microsoft world equivalent of Objective-C for Mac, but it is quickly becoming a favourite for cross-platform web apps. HTML5 – The HTML standard will make your apps compatible on desktop as well – indeed, that‘s what it was designed for. Still being improved, but very strong when coupled with JavaScript (below.