WHOIS and RDAP — how to check domain information
Author: Domeny.ForSale editorial team Published Updated
In brief: WHOIS and RDAP let you check a domain’s technical and registration data, including its status, registration dates and DNS servers. RDAP is the newer, structured successor to WHOIS, but the information visible depends on the registry, the domain operator and data protection rules. The absence of an owner’s name does not mean that the domain is available or was registered anonymously.
How WHOIS and RDAP differ
WHOIS is an older protocol that provides domain information in text format. Individual registries may use different field names and format their results differently, which can make automated comparisons of WHOIS records difficult. Queries are made through a web form or a client using the WHOIS protocol.
RDAP, or Registration Data Access Protocol, delivers data in a standardised JSON structure over HTTP. It makes it easier to identify the entity responsible for the response, handle referrals to the appropriate registry, and distinguish between contacts, events and statuses. To someone checking a single domain, the two tools may look similar, but RDAP is more convenient for applications and automation.
The name “WHOIS” is also used informally for any domain data lookup tool, even when the service retrieves information through RDAP. The response format or the tool’s documentation indicates which technology is used behind the scenes, rather than the label on the button.
How to check a domain step by step
The safest starting point is the relevant registry’s official lookup tool or a service that directs an RDAP query to the appropriate operator. A registry manages a particular extension, such as a country-code or generic top-level domain. Third-party services are convenient, but they may display delayed data or add their own interpretations.
The practical procedure is as follows:
- Enter the full domain name without
https://, a path or a slash, for exampleexample.comrather thanhttps://example.com/oferta. - Check that the response concerns exactly the right extension and spelling. A domain containing national characters may also be shown in Punycode notation beginning with
xn--. - Read the domain status, event dates, registrar and name servers.
- If the result comes from an arbitrary lookup service, compare the key fields with the response from the official registry or the appropriate RDAP server.
- Before buying or taking legal action, confirm the status directly with the registrar and check the relevant registry’s rules.
Example: a domain displays a page with an error message, but RDAP shows an active registration and assigned name servers. Such a domain is not automatically available for registration — the owner may simply not have configured the website.
How to interpret the key fields
Domain status describes the domain’s state in the registration system. Lock-related statuses may prevent the domain from being transferred, updated or deleted. Their precise meaning must be interpreted according to the rules for the particular extension, because not all registries use the same set of labels.
Dates may include the creation of the record, its last update and the end of the current registration period. The expiry date does not always indicate when the domain will become available to a new registrant. After the paid period ends, renewal, quarantine or deletion stages may apply, depending on the registry’s and registrar’s terms.
Name servers indicate the infrastructure handling the domain’s DNS. However, they do not reliably reveal the hosting company or the website owner. The servers may belong to an external DNS operator, while the website runs with another provider.
The registrar is the company that handles domain registration on behalf of the registrant. The record may also include a contact for reporting abuse. The registrar should not be confused with the registry, which maintains the central database of names under a particular extension.
Why the owner’s details may be hidden
A public result often does not include the registrant’s first name, surname, address or direct email address. Data may be restricted because of privacy protection, registry policy, the type of registrant or a service that acts as a contact intermediary. Instead, the tool may show a contact form, an address that forwards messages or a label indicating that the data is not public.
WHOIS and RDAP are not intended to confirm that the entity presented on a website is the actual owner of the domain. When assessing a shop or a business partner, you need to check the company details, terms and conditions, contact channels and payment method separately. The domain’s age alone does not prove the service’s trustworthiness either, because the name may have changed hands.
What to do with an ambiguous result
If different tools show different dates or statuses, give priority to the current response from the relevant registry or its RDAP service. You should also distinguish between missing data and a query error: a message stating that an extension is not supported does not confirm that the domain is available.
Before registering, check availability in the registrar’s system. Before buying a domain from its current registrant, verify whether it can be transferred and how payment can be settled securely. Always confirm the current renewal periods, locks and data publication rules in the relevant registry’s terms.
See also: How to monitor domains similar to your brand?
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