Build Mobile app in React Native framework with Mongo DB stitch

Looking for an expert developer who can help in building a mobile app in React Native framework with Mongo DB stitch. The app is similar to the many freelance apps out there. There are users, experts/service-providers/vendors who sell their services to the users/buyers. This mobile app acts as a platform for interaction between users and experts that involves transactions and integration with Payment Gateways. Payment gateway can be considered as a separate effort. I am specifically looking for an expert who has already developed similar kind of app so that we don’t lose time in reinventing. We have a detailed design document and can walk through to finalize the scope and deliverable. I am looking for a ballpark figure of how much it costs. We can finalize the final bid after detailed walkthrough. CONTACT ME, ONLY IF YOU HAVE DONE A SIMILAR FREELANCE KIND OF PROJECTS. At a high level: Technical 1. Platform Support : Android and iOS [login to view URL] / Services to use: React-Native Mobile Application Framework. 3. Cross-platform support (Same Code Development should work for both Android and iOS). 4. Seamless Cross-Platform. React components wrap existing native code and interact with native APIs via React's declarative UI paradigm and JavaScript. 5. Functional Component Programming is recommended for development (or class?) 6. Authentication and Authorization integration with Mongo DB Atlas + stitch (any other?) 7. Sign-in via facebook / twitter / linkedin / Google 8. Mongo DB Atlas Real time Database with stitch etc. Functional: Landing page, Home Page, Search, Vendor Details, user and vendor profile etc.