I've been wrecking my brain about this for a few days. I'll run my scenario by you and hopefully you can help me. In my head this is how it goes: I have an Android App. I want my Android App to make (function) calls to a MongoDB database via a Ruby Interface on the Server. e.g. Android app sends a HTTP GET ? with the function name, let's say getFriends for this user Ruby Interface receives this request from the app, grabs a thread from a thread pool and calls the appropriate function call implemented in Ruby, to the Mongodb. Ruby Interface gets results from Mongodb and sends a HTML POST to the Android app. So that's how I think it works. I know about the ruby driver for mongo db, and interacting with the mongodb from ruby but, how do I make a ruby back end listen for incoming messages and should these messages be done through sockets or a http interface ala Net::http in ruby?