What is RDAP? The Evolution of Domain Registration Data

Why the Internet Needed RDAP

For over 35 years, domain registration lookup relied on the WHOIS protocol (RFC 3912). WHOIS suffered from severe structural limitations: - Unstructured, inconsistent text formats across different registrars. - Lack of internationalization (Unicode / IDN support). - Inability to provide tiered, authenticated access for GDPR compliance. - Vulnerability to port 43 blocking by enterprise firewalls.

RDAP (Registration Data Access Protocol), specified in RFC 7480–7484, standardizes domain, IP, and ASN registration queries over secure HTTPS.

RDAP vs Legacy WHOIS Comparison

Example: A Trimmed RDAP Response (Illustrative)

{
  "objectClassName": "domain",
  "handle": "2138514_DOMAIN_COM-VRSN",
  "status": ["client transfer prohibited"],
  "events": [
    { "eventAction": "registration", "eventDate": "2019-03-11T00:00:00Z" },
    { "eventAction": "expiration", "eventDate": "2027-03-11T00:00:00Z" }
  ],
  "nameservers": [{ "ldhName": "ns1.example-registry.net" }]
}

Every field here is machine-parseable JSON with a documented schema — contrast that with legacy WHOIS, where the same information might appear as `Registry Expiry Date:`, `Expiration Date:`, or `paid-till:` depending on which registrar formatted the response.

Query Registration Data Online

Query live RDAP servers and examine structured registrar records with our WHOIS & RDAP Lookup Tool.