Cross-platform app application

I am looking to hire a mobile app developer to assist in building a a platform (web-based and app based applications) for a sharing economy project, similar to Uber and Airbnb. It is a simple concepts but complicated. Apps specifications User systems ( Seeker and provider), each has their own profiles which contains photos, rates. For provider profiles, should show their speciality, and services they are offering, and rates seeker profiles what they are looking. All the details will be provided after the offer is accepted. you will be paid based on an hourly rate. So efficiency is a must.