I have the follwoing folder sturcture parent_directory -client_side -server_side

I want to write a code in server side as a Rest API so that whenever the api is called with a get request taking parameter username , a React component is created in client_side folder and React-route-dom is also created for routing to that file so now i have something like this -> www.mainwebsite.com/username1 then after some other request -> www.mainwebsite.com/username2

How can i achieve this ? pls help!

Also in every webpage of each user , there will be the user's online SHOP for selling goods

PLS HELP