I have an angular application that currently handles tenants(customers) using our software to have their own online store load up based on query params. So https://my-site.com is the main domain. Let’s say a user signs up for our app. They will have a url https://my-site.com/storeId=someId which will route them to their store.

I want to change it so that when the user signs up, a subdomain is created https://subdomain.my-site.com which redirects to https://my-site.com/storeId=someId and loads up their store.

The application backend is NodeJs and Express and both the frontend and backend are deployed to heroku. The heroku app also has a custom domain.

Is there a way I can programatically have it so that the subdomain is automatically added to heroku and I can use an express or some middleware route or something similar to detect the subdomain and process the redirect.

There are very few posts I found about this and the few that are there are not useful or point to heroku documents which also don’t fully resolve my question. Some posts I looked at are:

Subdomain setup for Heroku

Dynamically creating subdomains on Heroku with nodeJS?

Subdomain alias in nginx and nodejs/express