With Heroku you can add custom domain to your Heroku app.

If you follow my previous tutorial where we create an IONIC + react app and we deploy it to Heroku.

On these steps, I will show you how you can use the Heroku application with your own domain name.

1. Go to the Heroku Dashboard:

2. In the Heroku Dashboard, click the "Add Domain" button

3. Populate the following fields according to your settings. TIP. You can add any subdomain name you want here. I am using ionic-react-math.example.com, but you can use anything, for example: myapp.example.com, anything.example.com - Whatever You want!
Domain Name: ionic-react-math.example.com

4. Click Next, on the next screen you will get a Congratulations message:

5. Now go to your Registar's domain name management control panel. For this examplek, I will be using CloudFlare.

6. Go to the CloudFlare domain name dashboard:

7. Click on the "Add Record" button and populate the following fields:

Select Type: CNAME
Name: ionic-react-math
Target: [SECRET].herokudns.com
Click Save

8. This make take a while to process. Usually took me about 10 minutes or propragate.

9. Visit your sub domain name with your app hosted on Heroku:

10. https://ionic-react-math.example.com