Kévin Dunglas Founder of Les-Tilleuls.coop (worker-owned cooperative). Creator of API Platform, Mercure.rocks, Vulcain.rocks and of some Symfony components. DNS comes with a set of rules defining valid domain names. A domain name cannot exceed 255 octets (RFC 1034) and each label cannot exceed 63 octets (RFC 1035). It can contain any character (RFC 2181) but extra rules apply for hostnames (A and