HTTP endpoints within Projects can claim custom subdomains
under val.run. To choose a custom subdomain, click the edit button in the
preview pane and choose a name.
Subdomain naming
Subdomain names need to be valid for the DNS system, so they can contain
letters, dashes, and numbers, but they cannot contain two consecutive dashes
--, or start or end with a dash. They can be anywhere from 3-63 characters
long.
Claiming and changing subdomain names
Subdomains are first-come first-served: once you claim a subdomain, it is attached to your account and can be used for your HTTP endpoints.
For security reasons and to prevent subdomain takeovers, if you claim a subdomain name and rename an HTTP endpoint away from that name, the old name will not be accessible to anyone else for a certain period of time.
Due to the exclusivity of subdomains, there are limits on how many domains you can use in your account and how many times you can change the subdomain of an HTTP endpoint.
Custom domains
You can go even farther with custom domains, which allow HTTP endpoints to be hosted behind any top-level domain that you purchase, or subdomain of a domain that you own.