I am very biased, but I think there are a lot of benefits to Node.js for mobile back ends. High performance, highly scalable, and really quick to develop in.
It walks you through pretty much all the steps, and it's pretty fast. Might be a good place to start just to see if Node.js is for you. Feel free to reply if you have specific questions about Node and mobile APIs, I'll try to answer what I can.
--Jordan