Mobile Application (Android, iOS)

I need an experienced mobile App developer: The project is a e-commerce mobile platform that does not have a front content of items sold, items sold are exchanged between two users one being the seller and the other being the buyer. Notification used Short Messaging Services (SMS) exchanged between the two users and email. Payment gateway to be incorporated are stripe, PayPal etc. Functionalities includes Database for seller to load items sold, Subscriptions etc.
Full spec to be exchange with successful bidders.