RDAP vs WHOIS: what changed?

The short version

WHOIS was created when the internet was much smaller. A WHOIS server usually returns a block of plain text, and every registry can format that text differently. RDAP returns structured JSON over HTTPS. That makes it easier for software to identify dates, entities, status codes and links without guessing where each value appears.

For users, the purpose is familiar: check a domain's registrar, dates, nameservers, status and any public contacts. The important difference is how reliably clients can find and interpret the answer. Domain Readout uses RDAP while retaining the familiar “WHOIS lookup” language people still use when searching for registration data.

What RDAP improves

How an RDAP domain lookup works

A client first identifies the domain ending, such as .comor .uk. It checks the IANA bootstrap registry to discover the correct RDAP base URL, then requests the domain object from that service over HTTPS. The response can contain events, entities, nameservers, status values, notices and links to related records.

This discovery step matters. It means the lookup can reach the registry responsible for the top-level domain instead of relying on a manually maintained list or an unofficial data copy. Domain Readout also links to the returned source so technical users can verify the raw JSON record.

Why information may still be hidden

RDAP improves delivery, but it does not make private registration data public. Registries and registrars may redact names, addresses, email addresses or telephone numbers because of privacy law and policy. A redacted field is not evidence that the domain is suspicious.

RDAP can describe redaction more precisely than a plain-text WHOIS response, but publication policy still belongs to the registry, registrar and applicable rules. Read our guide to why WHOIS and RDAP contact data is redacted for the practical implications.

Which result should you trust?

Use the record returned by the authoritative service for the domain’s registry. Note the lookup time, follow the source link, and treat registration data as one signal rather than proof of legal ownership. A registrant, registrar and website operator can be different parties.

If the question is “who is my registrar?”, look for the entity with the registrar role and confirm it using the registry source. If the question is whether a name is available, a missing RDAP record is only one signal; registrar checkout is the final confirmation.

Is WHOIS gone?

The word WHOIS remains common shorthand for a domain registration lookup. The underlying legacy protocol, however, is being replaced in important parts of the domain ecosystem. ICANN moved registration data access for generic top-level domains to RDAP, and Nominet has published transition guidance for the .uk namespace. Tools may still label a search “WHOIS” even when RDAP supplies the result.

For a practical demonstration, run a free RDAP domain lookup and compare the readable result with the linked source record.