WHOIS Lookup

Look up domain registration information using RDAP (Registration Data Access Protocol).

This tool uses RDAP (Registration Data Access Protocol), the modern replacement for WHOIS. Some information may be redacted for privacy protection depending on the registrar's policies.

UtilityTool

About WHOIS Lookup

This WHOIS Lookup tool provides access to domain name registration data by utilizing the modern Registration Data Access Protocol (RDAP)[18]. It retrieves authoritative information directly from domain registries and registrars, presenting a structured overview of a domain's public record. The data includes the sponsoring domain name registrar[5], critical dates such as registration creation and expiration, the domain's current status codes, and the assigned name servers that handle its DNS[3] resolution. It also retrieves contact information for the registrant, administrator, and technical points of contact, subject to privacy redactions.

The tool is a successor to clients based on the legacy WHOIS[21] protocol, a standard originally specified in RFC 3912[22]. The original WHOIS system, while foundational, suffered from significant limitations. It operated over an unencrypted, plain text connection on port 43 and lacked a standardized machine readable data format, resulting in inconsistent, difficult to parse output from different servers. Furthermore, it had no native support for internationalization, tiered access, or robust authentication, making it ill suited for the modern internet's privacy and security landscape.

RDAP was developed by the IETF[13] to address these shortcomings. As a RESTful[16] web service, RDAP queries are sent over HTTPS[10], providing transport layer security. Responses are delivered in a standardized JSON[14] format, as defined in specifications like RFC 9082[24] (Query Format) and RFC 9083[25] (JSON Responses). This structure ensures predictable, parsable data, supports international character sets, and provides a framework for differentiated access, allowing registries to manage access to sensitive data more effectively.

The governance of domain registration data is overseen by ICANN (Internet Corporation for Assigned Names and Numbers)[11], which has mandated the transition from WHOIS to RDAP for all generic top-level domains (gTLDs)[9]. This policy shift was accelerated by global privacy regulations, most notably the General Data Protection Regulation (GDPR)[8] in Europe. GDPR's strict rules on personal data necessitated the redaction of registrant information from public view. RDAP's design, which includes provisions for authentication and authorization, is better equipped than WHOIS to handle these tiered access requirements, separating public data from information available only to legitimate, credentialed users.

An RDAP lookup follows a defined process to ensure data authority. When a query is initiated for a domain, the client first consults a bootstrap service, managed by the IANA (Internet Assigned Numbers Authority)[12]. This service redirects the client to the correct RDAP endpoint for the specific Top-Level Domain (TLD)[20] in question. The client then sends its query to that authoritative server, which belongs to the responsible domain name registry[6]. This redirection ensures that the retrieved data is sourced directly from the organization that manages the TLD's records, guaranteeing its accuracy and timeliness.

How to Use

  1. Enter the complete domain name (e.g., example.com) into the search input field.
  2. Click the 'Lookup' button to initiate the query process.
  3. The tool performs a bootstrap lookup to find the authoritative RDAP server for the domain's TLD.
  4. A secure HTTPS request is sent to the authoritative server to fetch the registration data.
  5. Review the structured registration details presented, including registrar, key dates, status, and name servers.

Frequently Asked Questions

What is the primary difference between WHOIS and RDAP?

WHOIS is a legacy protocol that transmits unstructured plain text over an insecure connection. RDAP[18] is its modern successor, a secure HTTPS[10] based protocol that returns structured JSON[14] data, supports internationalization, and provides a framework for tiered access to data.

Why is some domain contact information redacted or missing?

Due to data privacy regulations like the GDPR[8], domain registrars and registries are required to protect personally identifiable information. As a result, details like the registrant's name, address, and email are often redacted from public WHOIS and RDAP outputs.

What do domain status codes like 'clientTransferProhibited' mean?

These are Extensible Provisioning Protocol (EPP)[7] status codes, defined in RFC 5731[23]. They indicate the state of a domain name. For example, 'clientTransferProhibited' is a status set by the registrar to prevent unauthorized transfers of the domain.

What is the role of IANA in the lookup process?

The IANA[12], a department of ICANN[11], operates the bootstrap service for RDAP. This service directs RDAP clients to the correct authoritative registry server for any given Top-Level Domain[20], ensuring queries are sent to the right place.

Can I look up IP addresses or ASNs with this tool?

This tool is specifically for domain names. IP address blocks and Autonomous System Numbers (ASNs)[2] are managed by Regional Internet Registries (RIRs)[17] like ARIN[1] and RIPE NCC[15], which operate their own RDAP services for those resources.

What does the 'DNSSEC: signed' status indicate?

DNSSEC (Domain Name System Security Extensions)[4] adds a layer of security to the DNS[3]. A 'signed' status means the domain has published cryptographic signatures for its DNS records, allowing resolvers to verify that the information they receive is authentic and has not been tampered with.

What is the difference between a 'thin' and a 'thick' registry?

In a 'thin' registry model, the central registry[6] for a TLD stores only minimal data, such as the sponsoring registrar, while the registrar holds the full registrant details. In a 'thick' model, the registry stores the complete, detailed registration record. ICANN[11] policy now requires a thick model for all gTLDs[9].

What is a Request for Comments (RFC)?

A Request for Comments (RFC)[19] is a formal document from the IETF[13] and other bodies that describes methods, behaviors, research, or innovations applicable to the working of the Internet. RFCs define the technical standards for protocols like WHOIS (RFC 3912[22]) and RDAP (RFC 9082[24], RFC 9083[25]).

Sources (25)
  1. Wikipedia: American Registry for Internet Numbers (ARIN)
  2. Wikipedia: Autonomous system (Internet)
  3. Wikipedia: Domain Name System (DNS)
  4. Wikipedia: Domain Name System Security Extensions (DNSSEC)
  5. Wikipedia: Domain name registrar
  6. Wikipedia: Domain name registry
  7. Wikipedia: Extensible Provisioning Protocol (EPP)
  8. Wikipedia: General Data Protection Regulation (GDPR)
  9. Wikipedia: Generic top-level domain (gTLD)
  10. Wikipedia: HTTPS
  11. Wikipedia: ICANN
  12. Wikipedia: Internet Assigned Numbers Authority (IANA)
  13. Wikipedia: Internet Engineering Task Force (IETF)
  14. Wikipedia: JSON
  15. Wikipedia: RIPE NCC
  16. Wikipedia: REST
  17. Wikipedia: Regional Internet registry (RIR)
  18. Wikipedia: Registration Data Access Protocol (RDAP)
  19. Wikipedia: Request for Comments (RFC)
  20. Wikipedia: Top-level domain (TLD)
  21. Wikipedia: WHOIS
  22. IETF RFC 3912: WHOIS Protocol Specification
  23. IETF RFC 5731: Extensible Provisioning Protocol (EPP) Domain Name Mapping
  24. IETF RFC 9082: Registration Data Access Protocol (RDAP) Query Format
  25. IETF RFC 9083: JSON Responses for the Registration Data Access Protocol (RDAP)

About Matt George

I'm Matt George, a software engineer in the startup space. I run my own shop building software for early-stage founders, and I love making free tools and experiences that people actually use. Enjoy using WHOIS Lookup!

More Free Tools

StatescapePaste a table of US states with counts and percentages, get a clean choropleth map with the values printed on each state, and download it as a high resolution PNG or SVG.iMessage GeneratorCreate a fake iMessage mockup on an iPhone 16 Pro. Type both sides, switch blue or green bubbles, and download a JPG.Add Text to ImageUpload a photo, type your caption, style the color, outline, font, and size, then drag it into place and download. A simple meme and caption maker.Case ConverterChange text to UPPERCASE, lowercase, Title Case, camelCase, snake_case, and more.Remove Line BreaksStrip line breaks and join broken text into one clean block.Text SorterSort lines alphabetically A to Z or Z to A, remove duplicates, and ignore case.