What is RDAP?
RDAP — the Registration Data Access Protocol — is the modern, structured replacement for WHOIS. If you've ever run a domain lookup, you've used the system RDAP now powers.
Why WHOIS needed replacing
WHOIS dates to the early internet. It returns free-form text over port 43 with no standard format — every registry formatted its output differently, there was no proper support for non-English characters, and it had no consistent way to handle access control. That made it fragile to parse and increasingly unfit for a privacy-regulated, international internet.
What RDAP does differently
RDAP answers the same question — who registered this domain and what's its status — but returns clean, predictable JSON over standard HTTPS. It supports internationalised domain names, has a defined query structure, and uses standard web mechanisms for redirection and access. Because it rides on HTTPS, tools and services can query it the same way they'd call any modern web API.
The transition
ICANN required generic TLD registries and registrars to support RDAP, and it became the authoritative registration-data source for gTLDs in early 2025. Most country-code TLDs have followed, though some still rely on legacy WHOIS.
What you get back
A typical RDAP response includes the registrar and its IANA ID, an abuse contact, the domain's status codes, nameservers, key dates (created, updated, expires), and whether DNSSEC is enabled. Registrant personal details are usually redacted for privacy.