Development of Infra service site including user authentication and billing

There is a service created internally The purpose is to make it online and make it public. I am looking for a PHP engineer who can build authentication, billing and infra construction. Since there is a demo page of the service itself, I think it will follow the image of its design. is it possible to ask for design together? ◾️ System contents The service itself is content creation and download. That part was already built. The service itself page is one page. In cooperation with the service, I would like to request the development of a WEB system that includes the entire process of authentication / billing / download by billing. >> Responsibility : UI / UX design and construction considering usability Design ※ Consultation required Infra design, construction System design and construction >> Functions list : User authentication (Email, google, Twitter) User management (registration, deletion, password change) Billing (Subscription) 3D Model display (because there is Viewer part, want connection with API for display. Linkage with existing content (simple FileDL and display part [3D])) Download 3D Model according to billing status Other Help screens, etc. >> Other : Regarding storage, the capacity is relatively large because 3D Model is handled. >> Materials provided : This document Viewer part source code Demo Page URL DB definition of 3D Model part URL to be returned by PHP server required for 3D Model display Direcotry structure in which 3D Model is stored