RDAP
RDAP (Registration Data Access Protocol) is the modern HTTPS-based replacement for WHOIS, standardised by IETF in 2015. ICANN required all gTLD registries and registrars to support RDAP by January 2025, when WHOIS for gTLDs was officially sunset. RDAP returns structured JSON, supports authenticated access, and is the canonical way to look up domain registration data today.
Also known as: Registration Data Access Protocol
In depth
RDAP is a query protocol defined in RFCs 7480-7484. Unlike WHOIS, which returns unstructured text over a 1980s-era TCP port-43 connection, RDAP runs over HTTPS and returns standardised JSON. This makes it programmatically usable, scalable, and aligned with modern security expectations.
The IANA maintains a public RDAP bootstrap registry that maps each TLD to its responsible RDAP server. Looking up a .com domain hits Verisign's RDAP server; looking up a .org hits Public Interest Registry's; and so on. Most registrars also operate their own RDAP endpoints for additional registration details.
ICANN finalised the RDAP transition for gTLDs on January 28, 2025. As of that date, gTLD registries and registrars are required to provide RDAP and are no longer obligated to provide WHOIS port-43 service (though many still do for backward compatibility). Country-code TLDs (ccTLDs) operate under their own policies and have varying degrees of RDAP support.
For domain monitoring tools like snooze.domains, RDAP is the primary lookup mechanism. The structured response includes EPP status codes, registrar information, dates, and (where not redacted by GDPR) contact information.
Examples
- A typical RDAP query: GET https://rdap.verisign.com/com/v1/domain/example.com — returns JSON with status, registrar, dates, and entities.
- IANA bootstrap query: GET https://data.iana.org/rdap/dns.json — returns the master mapping of TLDs to RDAP servers.
- Authenticated RDAP via ICANN's RDRS allows access to redacted PII for verified law enforcement and intellectual property holders.
Frequently asked questions
How is RDAP different from WHOIS?
WHOIS returns unstructured text over TCP port 43; RDAP returns structured JSON over HTTPS. RDAP supports authentication, internationalisation, and pagination. WHOIS does none of these.
Is WHOIS still available?
For gTLDs, ICANN officially sunset WHOIS on January 28, 2025. Most registries and registrars still provide WHOIS for backward compatibility, but RDAP is now the canonical protocol. ccTLDs vary widely.
Does RDAP show registrant contact info?
Usually no, post-GDPR. Personal contact information is redacted by default. Authenticated RDAP via ICANN's RDRS allows verified parties to request unredacted records.
How do I find the RDAP server for a TLD?
Query the IANA bootstrap registry at data.iana.org/rdap/dns.json. It maps every TLD to its authoritative RDAP server.
Are there RDAP rate limits?
Yes, set per-server. Limits vary widely — some registries publish them, many do not. Operators that hit a limit get HTTP 429 responses with a Retry-After header. ccTLDs are often stricter than gTLDs.
Related terms
References
Watch a domain you want to buy — snooze.domains tracks the lifecycle and emails you when it changes status. Free, up to 100 domains. Start watching — free