How Does the Domain Availability Checker Work?
The checker sends one query per TLD to the registry that runs it, with RDAP (Registration Data Access Protocol). RDAP replaced WHOIS for generic TLDs in 2025. When the registry has no record of the domain, the domain is available. When the registry returns a record, the domain is registered.
An available result means nobody has registered the name. It does not reserve it for you: register it with a registrar to claim it. Some registries also hold back premium or reserved names that show as available here.