Backend Development for Comparison Engine

We are looking to have an algorithm designed for an emerging tech startup. Our algorithm needs to understand various e-commerce API and needs to evaluate and analyze their data. The main purpose of the application is to compare pricing for online products. In addition to simple comparison, the data needs to be modulated to calculate tax and shipping costs. Once this has been performed for each site, it must draw conclusions and show the best results to the customer. In order to do this efficiently, we will tailor our own API simultaneously, thus allowing our site to interact with different points of different e-commerce APIs.