Data processing functions and user authentication. C#/Xamarin (windows/ios/Android)

Hello, We are looking for an experienced C#/Xamarin coder who has done similar work before. This will be a C#/Xamarin forms application that needs to run on a windows desktop/Android/IOS/OS X. The application involves mainly user authentication and login functions that uses existing python API to communicate with AWS (dynamodb, S3) The project is well defined down to the logic level. I will send a detailed, step-by-step block diagram once your bid is under consideration. If you are an experienced C#/Xamarin coder with high rating, good work ethic, eye for detail and sound coding practices please apply. I am not looking for the lowest cost coder I can find. I am willing to pay up for high quality work done right. I will offer bonus over our agreed amount and additional work for job well done. This project pays only when fully finished/tested code is delivered so do not apply if this is not acceptable to you. Thank you for biding and good luck.