It depends on what you want to do with the data. The API just gives you every quote/trade at every level of the book for the sources you subscribe to. It's completely up to you what you want to do from there. For me, I've done quite a bit of development but if you just want the latest best price then it would be trivial to code in about 3 or 4 lines.. The API doesn't offer any historical info, but I don't believe that is something an API should offer anyway.. that is best handled by some more batch oriented process. Also, you have to construct the bars, etc yourself if thats what you want to do. The api is fairly elegant in its simplicity.. saves you the headache and overhead of developing to complicated APIs.