WHOIS Domain Lookup

What is WHOIS / RDAP?

WHOIS is the original protocol for querying domain registration data, dating back to the early days of the internet. Its modern replacement is RDAP (Registration Data Access Protocol), defined in RFC 9082 and RFC 9083. RDAP returns structured JSON over HTTPS, making it machine-readable, secure, and CORS-friendly for browser-based queries.

This tool queries RDAP servers directly from your browser. The data returned includes the registrar, registration and expiration dates, nameserver delegation, domain status codes, and DNSSEC signing status. RDAP is gradually replacing legacy WHOIS across all registries and registrars.

RDAP vs Traditional WHOIS

Domain Registration Lifecycle

Domains go through several stages: registration (active use), expiration (grace period where the registrant can renew), redemption (post-expiry hold, usually 30 days), and pending delete (5-day countdown before release). The status codes in RDAP responses reflect where a domain currently sits in this lifecycle. Monitoring expiration dates is critical to prevent accidental domain loss, which can lead to email delivery failures and brand hijacking.

Why DNSSEC Matters

DNSSEC (DNS Security Extensions) adds cryptographic signatures to DNS responses, preventing attackers from forging DNS answers. When a domain shows delegationSigned: true in RDAP, it means the parent zone has a DS record pointing to the domain's DNSKEY, establishing a chain of trust from the root. DNSSEC is a prerequisite for DANE (DNS-based Authentication of Named Entities), which provides certificate pinning for SMTP connections via TLSA records.