How to deploy to Netlify or Vercel and use custom subdomain with HTTPS

[cbaucom]

Hi, I've successfully set up everything just fine in Heroku by following the docs but do not want to pay a monthly fee in Heroku just to add HTTPS to my custom domain. I am wondering if someone could walk me through other (free) options to get this working. Can this be run on Netlify or Vercel? I did try Netlify but it did not work out of the box.

Ideally, I would host this somewhere free and create a subdomain to a domain I already own to use like feedback.mysite.com