The Short Answer: Use RDAP First, WHOIS Only Where It Still Lives
If you look up a domain today and type the word WHOIS, you are probably using the wrong name for what you actually need. Since 28 January 2025, RDAP — the Registration Data Access Protocol — has been the definitive source for generic top-level domain (gTLD) registration data, and most gTLD registries and registrars are no longer required to run the old WHOIS service at all. That ICANN ruling is the single most important fact in this comparison.
That does not mean WHOIS is dead everywhere, and it does not mean your old habits are useless. The right tool depends on the job: a quick human check, an automated expiry monitor, a brand-protection investigation, or a country-code domain each point to a different answer. This post explains what each protocol is, how their answers differ, where WHOIS still works, and how to read an RDAP result without a developer background.
If you just want the answer for one domain, run a lookup with Nomlen's free WHOIS checker. The rest of this post explains what that result means.
What WHOIS Actually Is
WHOIS is one of the oldest lookup protocols on the internet. Its roots go back to RFC 812 in 1982, and the version most people used was formalised in RFC 3912 in 2004. The design is deliberately simple: open a connection to TCP port 43, send a domain name as plain text, and read back whatever the server sends in return.
That simplicity was also its flaw. There was no fixed response format, so every registry and registrar printed its own layout, with varying field names and date formats. A human could usually make sense of it; a script could not do so reliably without a separate parsing rule for each operator. There was no encryption, no authentication, and no way to give different requesters different levels of access.
For decades that did not matter much, because registration data was largely public. Then the EU's General Data Protection Regulation (GDPR) took effect in May 2018, registrant contact details were redacted on a large scale, and the protocol had to be rebuilt, not patched.
What RDAP Actually Is
RDAP is that rebuild. Developed by the Internet Engineering Task Force (IETF), it was first published as RFCs 7480–7484 in 2015 and later updated by RFCs 9082 and 9083; its core is now Internet Standard STD 95. Instead of plain text over port 43, RDAP is a REST-style protocol over HTTPS that returns structured JSON — the same machine-readable format used by most modern web APIs.
Three design choices matter most:
- Structured data, not text. Every RDAP answer uses the same field names and structure, so a program can read the registrar, dates, status codes and nameservers directly, without guessing how a particular registry formatted its reply.
- Automatic server discovery. RDAP uses a bootstrap registry, defined in RFC 9224 and published by IANA at data.iana.org/rdap/dns.json, that maps each top-level domain to its registry's RDAP base URL. A client reads that file and is routed to the authoritative source automatically, instead of relying on a hard-coded list of WHOIS servers.
- Tiered access. RDAP was designed so different requesters can legitimately see different data. A public, anonymous query returns the public fields; an authenticated requester with a legitimate interest can, where policy allows, see more. WHOIS had no such model — it was all or nothing.
The Timeline That Changed Everything
ICANN required all gTLD registries and registrars to operate an RDAP service by 26 August 2019, and the two protocols ran side by side for over five years. The decisive change came with ICANN's 2023 Global Amendment and its 27 January 2025 announcement: from 28 January 2025, RDAP became the definitive source for gTLD registration information, and registries and registrars were no longer required to provide WHOIS.
That wording matters. ICANN did not delete the WHOIS protocol, and the IETF has never deprecated RFC 3912. What expired was the obligation to run WHOIS. Many operators kept their services running, and some are retiring them on their own schedules — so an empty WHOIS result today may simply mean the operator is no longer required to run that service.
There are three exceptions. ICANN's FAQ confirms that, as of 28 January 2025, WHOIS is no longer required except for .com, .name and .post. The .com registry agreement still obliges the registry to run a WHOIS service on port 43 — so a claim that WHOIS is completely dead for .com is backwards.
RDAP vs WHOIS: The Full Comparison
Dimension | WHOIS | RDAP |
|---|---|---|
Transport | TCP, port 43, plain text | HTTPS, REST-style web requests |
Response format | Unstructured plain text; layout varies by operator | Standardised JSON with identical field names |
Encryption | None — queries and answers travel in the clear | HTTPS encrypts every query and response |
Parsing | One rule per registry; brittle and manual | One parser works for every compliant registry |
Server discovery | You must know the right server, or follow referrals manually | IANA bootstrap registry routes the query automatically |
Access model | All or nothing; same data to everyone | Tiered; public vs authenticated requesters can see different fields |
Internationalisation | ASCII-centric; non-Latin scripts unreliable | Unicode and internationalised domain names supported |
Scope | Domains (plus separate IP/ASN systems) | Domains, IP networks and ASNs in one model |
Error handling | Free-text messages, inconsistent | Standard HTTP codes — a 404 means the name is not registered |
Standard | RFC 3912 (2004), roots in RFC 812 (1982) | RFCs 7480–7484, updated by 9082 and 9083; STD 95 |
Status for gTLDs in 2026 | No longer required (except .com, .name, .post); many operators still run it | Required and definitive since 28 January 2025 |
How to Read an RDAP Answer (Without Being a Developer)
A raw RDAP answer looks intimidating because it is JSON, but its structure is consistent:
What you want to know | Where it lives in RDAP JSON | What to watch for |
|---|---|---|
Is the domain registered? | The response itself — a 404 means it is not | Do not confuse "not found" with a failed lookup |
Who is the registrar? | The entity with the "registrar" role; its name is in the vCard "fn" field | This is the registering company, not necessarily the website host |
When was it created? | events, with eventAction "registration" | Creation date signals whether a site is established or brand new |
When does it expire? | events, with eventAction "expiration" | Expiry drives renewal and backorder decisions — see our guide to how expired-domain backorders work |
Is it locked or on hold? | status array (EPP codes such as clientTransferProhibited) | A transfer-prohibited status blocks moves even if you own the domain |
Where does it point? | nameservers, each with an ldhName field | Nameservers identify the DNS host, often different from the registrar |
Why is the owner hidden? | Redacted fields, and entities marked as redacted | Redaction is policy, not a fault — see whether domain privacy protection is worth it |
Which Should You Use? A Decision Guide for 2026
Checking one domain by hand
Use whichever lookup tool gives you a clean, readable answer — most good tools today query RDAP behind the scenes and present it in the old WHOIS style. Our earlier guide to what WHOIS is and how to look up who owns a domain still explains the questions to ask; only the plumbing has changed.
Monitoring domains or building a tool
Use RDAP, full stop. One JSON parser replaces dozens of registry-specific text rules, the bootstrap file removes the need to maintain a server list, and standard HTTP errors make failure handling sane. New automation written against port-43 WHOIS in 2026 builds on a service operators are no longer required to run.
Investigating a domain, or needing contact details
Start with RDAP for the authoritative record: creation date, registrar, status codes and nameservers are the spine of any investigation. But redaction limits what public lookups show. Since GDPR, most gTLD lookups return the domain, its dates and registrar, but not the registrant's name, address, phone or email — permanent ICANN policy, not a glitch, and it applies whether or not the owner bought a privacy add-on. For non-public data, legitimate requesters use ICANN's Registration Data Request Service (RDRS) or contact the sponsoring registrar. RDAP's tiered access is that mechanism; it is not a back door for the public.
Country-code domains (ccTLDs)
Do not assume gTLD rules apply. Country-code registries sit outside ICANN's gTLD contracts and set their own policies: some run RDAP, some still run WHOIS. If an RDAP lookup returns nothing for a ccTLD, check that registry's own lookup service before concluding the domain is unregistered.
The Mistakes People Still Make
- "WHOIS is dead, so my old lookup tool is broken." Not necessarily. Many tools labelled WHOIS already query RDAP, and many registries still run WHOIS. If a lookup fails, try the registry's own RDAP service or ICANN's Lookup tool before blaming the tool.
- "RDAP will show me the owner's name." No. RDAP changes how data is delivered, not how much personal data is public. Redaction survives the protocol change.
- "I should keep parsing WHOIS text because it still works for .com." It works for .com only because .com is an exception — building new tooling on the exception is the riskiest option here.
- "A 404 from RDAP means my query failed." In RDAP, 404 is the answer: the name is not registered. That is how RDAP-based availability checks work.
For most buyers, the protocol change is invisible — and that is the point. The one visible change worth remembering is the empty result: before 2025 it usually meant a parsing failure, whereas today it more likely means the operator stopped running WHOIS and your tool has not caught up — or, if the tool is RDAP-based, that the domain is genuinely available.
Frequently Asked Questions
Is WHOIS gone in 2026?
No. WHOIS is no longer required for most gTLDs since 28 January 2025, but the protocol itself was never deprecated, many operators still run it, and .com, .name and .post registries are still required to provide it. WHOIS is optional for most gTLDs now; RDAP is the required standard.
What is the main difference between RDAP and WHOIS?
Format and transport. WHOIS returns unstructured plain text over TCP port 43, with a different layout per operator. RDAP returns standardised JSON over HTTPS, with identical field names, automatic server discovery through the IANA bootstrap registry, and tiered access for different requesters.
Do I need an API key or special software to use RDAP?
No. Public RDAP lookups need no key. You can query a registry's RDAP endpoint from a browser or with a tool like curl, or use a lookup tool such as ICANN's Lookup service or Nomlen's WHOIS checker, which handles the protocol for you.
Will RDAP show me who owns a domain?
It shows the same public registration data WHOIS showed: registrar, dates, status codes and nameservers. Registrant personal details remain redacted for most gTLDs under post-GDPR policy. For non-public data, legitimate requesters use ICANN's Registration Data Request Service (RDRS) or contact the sponsoring registrar.
Why did my old WHOIS lookup stop working?
Most likely because the registry or registrar you were querying is no longer required to run WHOIS and has switched it off, or your tool still points at a retired port-43 server. Switch to an RDAP-based lookup, or check the registry's own RDAP service.
Does RDAP work for country-code domains like .uk or .de?
Sometimes, but not by the same rule. ccTLD registries set their own policies outside ICANN's gTLD contracts, so RDAP availability and the amount of data published vary by registry. Use that registry's own lookup service for ccTLDs.
Which should I use for automated expiry monitoring?
RDAP. One JSON parser works across registries, the bootstrap file finds the right server, HTTP status codes make errors explicit, and a 404 cleanly signals an unregistered name. WHOIS text parsing is brittle and built on a service that is no longer required.
