You cant go wrong either with Rails(Ruby) or Python (Django),they will help you develop your app quickly and both solutions are fun to use. I personally prefer

You cant go wrong either with Rails(Ruby) or Python (Django),they will help you develop your app quickly and both solutions are fun to use. I personally prefer Ruby while Python is easier to deploy on a server. But you'll attract more data scientists with Python when your prototype is mature. PHP : while easy to learn, i would not recommend it.It's an old badly designed language that has little future outside cmses.I only use it to customize CMSes today,i would not develop any app from scratch with it, furthermore writing PHP is awfull compared to Ruby and Python. NodeJS: While Javascript everywhere seems like a good idea(you'll have to learn Javascript to script the browser anyway), NodeJS use async programming , and async programming is hard,no matter what people say, furthermore Node is not mature yet, especially its libraries. Java(JVM):If you have time try it(Spring/Play/...). It will feel hard and verbose but You'll learn a lot of interesting concepts. If you want to code a prototype quickly forget about it. And Java has a lot of very good and mature librairies. So if you want to develop an app quickly and you care about how your code look like, go with Python or Ruby. If you have more time go with the JVM. Also check basic informations on these topics :HTTP,Rest,OAUTH you'll need them pretty quickly if you want to interact with Twitter.