RDAP Lookup

Look up domain registration data using RDAP — the modern, structured, JSON-based protocol that's replacing legacy WHOIS across the domain industry.

What is an RDAP lookup?

An RDAP lookup reads a domain's registration data through the Registration Data Access Protocol, the standard designed to replace WHOIS. Instead of a block of free text, RDAP returns structured JSON with defined fields, so every value has one clear meaning. It answers the same questions as WHOIS (registrar, dates, status, nameservers) in a far more dependable way.

RDAP is defined in a set of IETF standards, including RFC 9082 for queries and RFC 9083 for the JSON responses. Since January 2025, ICANN has treated RDAP as the official source of registration data for generic top-level domains such as .com, .net and .org.

How the RDAP protocol works

RDAP runs over normal HTTPS. A client first needs to know which server is responsible for an extension, and finds out from the IANA bootstrap registry, a published list that maps each top-level domain to its RDAP base URL. The client then requests that server's domain endpoint and receives a JSON document back.

That document can contain links to other RDAP servers. For many generic domains, the registry's answer includes a link to the registrar's own RDAP server, which may hold extra details. This tool shows that link when the registry provides it, but does not follow it automatically, so each lookup stays a single, quick request.

If an extension has no RDAP server in the bootstrap registry, the tool falls back to a legacy WHOIS query and labels the result clearly, so you always know which protocol supplied the data.

How to use the RDAP lookup tool

Enter a domain name such as example.org, without https:// or a path.
Run the lookup and check the "Data source used" line first: it tells you whether RDAP or the WHOIS fallback answered.
Read the server details: the RDAP server queried and, when present, the registrar's own RDAP server.
Review the registration fields: registrar, registration date, expiry date, DNSSEC and privacy signals.

What the RDAP results mean

Data source and servers

"RDAP" means the values were parsed from the registry's structured response. "WHOIS fallback" means the extension has no RDAP service yet. The server address shows exactly which registry endpoint was asked.

DNSSEC signed

RDAP includes a secure DNS section where the registry declares whether the domain is signed with DNSSEC. This is one of the fields that legacy WHOIS often cannot provide reliably.

Privacy or redaction likely

RDAP responses can mark fields as redacted. When personal data has been removed, the tool says so, rather than leaving you to guess whether the field is empty or hidden.

RDAP lookup compared with WHOIS

Both protocols describe the same registration, but they behave differently. WHOIS runs over port 43 and every registry formats its reply its own way, so one field can appear under several different names. RDAP runs over HTTPS, always uses the same JSON structure and finds the right server through a bootstrap list published by IANA. It also has standard error codes and proper support for internationalised domain names, which makes results far easier to compare between extensions.

Common uses

Getting clean, structured registration data you can trust field by field.
Checking whether a domain's extension supports RDAP before building an integration.
Confirming DNSSEC status as declared by the registry.
Comparing a registry-level answer with the registrar's own RDAP server.

Common problems and fixes

The result says WHOIS fallback. The extension is not in the RDAP bootstrap registry yet. This is common for country-code domains. The data is still shown, just with fewer structured fields.

Contact data is missing. Registries and registrars redact personal information by default. RDAP makes this visible instead of hiding it.

The lookup fails. RDAP servers occasionally rate-limit or go offline briefly. Wait a moment and try again.

Related tools

WHOIS Lookup gives the everyday registration view with status codes explained.
TLD Lookup checks whether an extension supports RDAP or WHOIS.
Domain Information shows the record in four clear sections.
Domain Expiry Checker focuses on renewal timing.

Frequently asked questions

What does RDAP stand for?

RDAP stands for Registration Data Access Protocol. It is the IETF standard for looking up who manages a domain name, an IP address block or an autonomous system number. It returns structured JSON over HTTPS and was created to replace the older WHOIS protocol, which returns unformatted text that differs from registry to registry.

Is RDAP replacing WHOIS?

Yes, for generic top-level domains. ICANN made RDAP the definitive source of registration data for domains such as .com, .net and .org in January 2025. Many country-code registries have adopted RDAP as well, but some still only offer WHOIS, which is why this tool falls back to WHOIS when a registry has no RDAP service.

Why is RDAP better than WHOIS?

RDAP uses a fixed JSON format, so each field has one defined meaning and tools can read it without guessing. It runs over HTTPS, supports standard error codes, can show which fields were redacted and can link to other servers such as the registrar's own. WHOIS returns free text that every registry formats differently.

What is the IANA RDAP bootstrap registry?

It is a public list published by IANA that maps each top-level domain to the RDAP server responsible for it. An RDAP client checks this list to find the right server before sending a query. If an extension is not in the list, there is no RDAP service for it yet.

Why does my RDAP lookup show a registrar RDAP server?

For many generic domains, the registry keeps a thin record and points to the registrar for extra details. The registry's RDAP answer then includes a link to the registrar's own RDAP server. This tool shows that link when it is present, so you can see where additional data may be held.

Can RDAP show the domain owner's contact details?

Only when the registry or registrar chooses to publish them. Under privacy rules most personal contact details are redacted, and RDAP marks those fields as redacted rather than leaving them blank. Organisation names and countries are sometimes still shown for company-owned domains.

Does RDAP work for IP addresses too?

Yes. The same protocol is used by the regional internet registries, such as ARIN and RIPE NCC, to publish who holds an IP address block. This page looks up domain names; to see who holds an IP address, use our IP WHOIS tool instead.