I have a mobile application written in Android/Java. We have coded to a particular API that uses gRPC and protocol buffers. It will have profiles, location tracking, images, messaging with read receipts and likes. Users should be able to search for other users in their area by periodically polling the server.
The candidate should propose a backend solution that can be scaled, indicate the language that will be used and databases which may be employed to scale this to multiple millions of users.
I will provide a protocol buffer file and a database schema that we began with. Additional requirements may be negotiated for more pay in the future, but I want to begin by completing the basic features at an agreed-upon price. But ultimately it MUST support the protobuf and grpc requirements I provide. It must support login with facebook and push notifications to android.