RDAP: The WHOIS Successor
RDAP (Registration Data Access Protocol) is the modern protocol for querying domain registration data — the structured successor to WHOIS, standardized by the IETF in the RFC 7480 series. It returns JSON over HTTPS with consistent field names, so expiry dates, status codes, and registrar details can be parsed reliably by software instead of scraped from free-form text.
Why RDAP replaced WHOIS
- •Structured JSON instead of unstandardized text — every registry's WHOIS output formatted dates and fields differently; RDAP output is machine-readable by design.
- •HTTPS transport with support for internationalized data and tiered access, none of which port-43 WHOIS could offer.
- •Authoritative discovery: IANA's bootstrap registry maps each TLD to its official RDAP endpoint, so you query the right server automatically.
- •ICANN sunset the gTLD port-43 WHOIS requirement on January 28, 2025; RDAP has been offered across gTLDs since 2019 and is now the definitive source.
Why investors care
RDAP is how you verify the registry's truth about your own portfolio: the real expiry date, the lock statuses, the lifecycle stage. Spreadsheet dates drift; the registry record does not. This is the layer Sourdough is built on — it enriches every domain in your portfolio with live RDAP data and flags changes, with a 7-day free trial.
Track your whole domain portfolio in one place
Sourdough is the system of record for domain investors: every domain, renewal date, cost, and sale across all your registrars. 7 days free, then $10/mo. $0 due today.
Frequently Asked Questions
How do I run an RDAP lookup?
Use ICANN's lookup service at lookup.icann.org, query a registry's RDAP endpoint directly (e.g. rdap.verisign.com for .com), or use any modern WHOIS tool — most now return RDAP data underneath.
Does RDAP work for ccTLDs like .ai?
Increasingly, but not universally. RDAP is mandatory in the gTLD space; ccTLD registries adopt it on their own schedules, and some still offer only traditional WHOIS.