WHOIS domain ownership lookup
Every time a domain gets registered, that record becomes public on a WHOIS server anyone can query. The text that comes back follows a decades-old protocol, and understanding the format explains why two lookups of the same domain sometimes return different data.
"com.br" is recognized as a single registrable suffix, not two separate TLDs, so the right WHOIS server to query is the ".br" registry (Registro.br), not a generic ".com" one.
WHOIS is not domain-only: the five RIRs (ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC) also run WHOIS servers to look up who an IP block was delegated to.
With no fixed schema, the only way to know a domain is free is recognizing boilerplate phrases like "No match for domain"; text carrying "Creation Date" and "Registrar:" already classifies as registered, even if the word "available" shows up elsewhere in the legal notice.
Start with the object type, then review events, statuses and entities. Only then inspect raw data. The common mistake is staring at one field while ignoring the combination of registrar, timeline, range, ASN, notices and DNS.
Since 2018, under the GDPR, registrars redact the individual registrant’s name, email and phone by default, showing "REDACTED FOR PRIVACY" or a proxy contact instead. The domain still has an owner, the personal data just stopped being public.
No. WHOIS (RFC 3912) returns free text over port 43 with no fixed format. RDAP (RFC 7482/7483) is the successor: query and response in structured JSON over HTTPS, easier for machines to parse.
Yes. The five Regional Internet Registries (ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC) keep their own WHOIS databases for IP blocks and ASNs, separate from domain databases.
Because RFC 3912 only standardizes the transport (plain text over port 43), not the content. Each registry and registrar picks its own fields and order, which explains the format difference between a ".com" and a ".com.br".
Pick a starting point, or type above:
The lookup runs on our server with timeout, short cache, SSRF protection and without storing the query in analytics. Analytics events only record aggregate tool usage, never the searched value.