BigCommerce and Shopify App Development

I need an app developed for BigCommerce and Shopify - you either need to have experience developing for both or need to go through and understand the documentation both services provide for development and their APIs. There will be coding(Java, Ruby, PHP, XML, and API) as well as a bit of designing(HTML and CSS) involved. I've got drawn concepts and a flowchart of what I want the app to do. Ideally, the app should be a fully integrated app: [login to view URL] [login to view URL] This is a general idea of what the app will do: when condition X is met, a pop up will appear on the webpage - customer interacts with popup and data is stored. When second condition is met, an action happens and the stastitics are recorded(internally and using URLs for Google Analytics tracking). The popup should work on desktops, tablets, and mobiles, like the AddThis Smart layers for example: [login to view URL] Buyer must be prepared to sign an NDA before discussing details.