Did you know? - The longest* looping alphabetical domain name here.
As each labels of a domain name may contain up to 63 characters, usually you can only put 2.423 A-to-Zs into it.
But there is a TLD .xyz, which is 0.115 A-to-Z. With this TLD, we've got total of 2.538 A-to-Zs, from M to Z, then A to Z twice!
*: As of , .xyz is the only TLD ending with xyz. For this reason, mnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvw.xyz is the longest, valid apex domain name with repeating alphabets.
Wanna go much longer?
You can add some 63-letters subdomains and get additional 2.423 A-to-Zs for each of them.
Or, you can create new TLD longer than .xyz (maybe 63-letters) and make your apex domain longer.
But don't forget that you cannot go further than 255-letters for hostnames, thus the longest possible hostname will consist of 63-letters sub-subdomain, dot, 63-letters subdomain, dot, 63-letters domain, dot plus 63-letters TLD and be 9.692 A-to-Zs.
Got longer? Congratulations! Now THE LONGEST is yours!
Please send me a message with your URL and let me place a link to the champion on this page.
Watch out! There's a pitfall!
Long hostnames are cool and legal. But, when you come to TLS, the coolness will become a problem. That's because, there is a limit of 64-characters for Common Name.
You might notice that this very site, with obviously lengthy hostname, is served via HTTPS. For this site, I set up a certificate with a shorter Common Name under another domain I own. And the lengthy name is listed as its Subject Alternative Name, which has no such limitation.