Testing web page with custom subdomain in a mobile devices, passing a test URL to co-workers, etc. I did this a lot, even though I have my own DNS server setup

Testing web page with custom subdomain in a mobile devices, passing a test URL to co-workers, etc. I did this a lot, even though I have my own DNS server setup for this purpose in my own LAN, I could see myself using this if I don't already have the DNS set up.