I would start with a basic save system, this would be a file saved on the clients machine but would be easily manipulated. If you’re good with server and coding. You could use the JSON plugin to securely transfer the information to a dedicated webserver. Since duping and hacking and all that would be quite easy.
This is no small feat, at least not for me. You may need to hire someone depending on your skill level.
here is a post on Reddit that will explain more avenues.