How to create sub-domain of any domain in react?


I want to create multiple sub-domain according user sign-up for eg:-
I have a domain :-
If John is register in that web site, then I want to create a sub-domain :-

Please advice me any solution.


As far as i know, react is not involved in anything with this.
This is a DNS issue, probably something like DNSMadeEasy and their API should fit your need.