Subdomain

A subdomain is a name created under a domain you already control: go.brand.com, link.brand.com, l.brand.com. You create as many as you like without buying anything, because the zone is yours to edit. In DNS terms each is a separate name with its own records, its own lifetime values and its own certificate — www.brand.com and brand.com are two different hostnames, not two spellings of one.

For short links a subdomain is the path of least resistance. It accepts a CNAME record, which every provider supports and which lets the platform change its own infrastructure without you touching DNS, and the certificate is issued automatically once ownership is verified. It also keeps concerns apart: link traffic on go, the website on www, so what happens to the reputation of one does not automatically follow the other.

The near-universal beginner error is typing the whole hostname into a provider panel that already appends the domain, producing go.brand.com.brand.com. Enter only the prefix, then check the saved record before waiting on verification.