RDAP Lookup

RDAP stands for Registration Data Access Protocol. Think of it as the modern, standardized replacement for WHOIS. Instead of returning unstructured text that every registrar formats differently, RDAP returns clean JSON with consistent fields. You query the IANA bootstrap to find the right registry server for a TLD, then send your domain query, and the server returns registration details, status codes, events, and nameservers in a predictable format. It's much easier to parse programmatically and handles privacy redaction more cleanly than legacy WHOIS.

Open an RDAP lookup tool, enter the domain (just the root, no protocol), and submit. The tool routes the query to the correct registry server using IANA's bootstrap file, then displays the response in readable format. You'll see the registrar name, registration and expiry events, EPP status codes, nameserver entries, and any notices about access restrictions. For deeper work, copy the raw JSON — it has more fields than the formatted view usually shows, including links to related entities like the registrar's contact page.

WHOIS is the old protocol — port 43, plain text, every registrar formats output their own way. RDAP is the modern replacement — HTTP-based, returns structured JSON, with proper bootstrapping so queries route to the right server automatically. RDAP also handles privacy and redaction more cleanly, with explicit notices about what's hidden and why. ICANN has been pushing registries to standardize on RDAP for years. For automated tools and audits, RDAP is much more reliable — WHOIS still works but parsing it is genuinely a nightmare.

Mostly because of GDPR and similar privacy regulations. After 2018, ICANN allowed registries and registrars to redact personal registrant data — name, email, phone, address — from public lookups. RDAP responses now usually show just "REDACTED FOR PRIVACY " or omit the entity entirely. To get owner details you need legitimate legal grounds and to go through the registrar's disclosure process. For most SEO and audit work, you don't need owner data anyway — registration events and nameservers are what actually matter.

Look for a few key sections."events " holds the date stamps — registration, last changed, expiration."status " lists the EPP codes like clientTransferProhibited or serverHold."entities " contains roles like registrar and registrant (often redacted)."nameservers " lists the NS hosts."links " point to related resources."notices " and "remarks " explain access restrictions or redaction. Once you've parsed a couple of responses, the structure becomes second nature. RFC 9083 is the spec if you want to go deeper into every field.

IANA maintains a bootstrap file at data.iana.org/rdap/dns.json that maps every TLD to its authoritative RDAP server URL. Tools should query this file (or cache it) and route domain lookups accordingly. So for .com it goes to Verisign's RDAP endpoint, for .org to PIR's, and so on. If a TLD isn't in the bootstrap, RDAP isn't supported for it yet — that's common with some ccTLDs. Always trust the registry's RDAP server over any aggregator or third-party copy.

Yes, when the registry publishes them. Both are returned inside the "events " array — look for events with action "registration " (creation date) and "expiration " (expiry date). You'll also often see "last changed " and sometimes "transfer ". But not every registry publishes every event — many ccTLDs intentionally omit expiration for privacy reasons, and some skip creation too. When the field is missing, it's usually a registry policy choice, not a tool bug. The registrar's dashboard remains the fallback for accurate dates.

Several reasons. Registries enforce rate limits to prevent abuse — running 200 lookups in a minute will get you a 429 response."Not found " usually means the domain doesn't exist (typo, expired and deleted, or never registered). It can also mean the TLD isn't supported by RDAP yet — check IANA bootstrap first. Temporary outages do happen, especially during registry maintenance windows. If you're hitting rate limits regularly, batch your queries with delays, or use a paid bulk lookup service for large audits.

Coverage is hit-and-miss. Check the IANA RDAP bootstrap file first — if the ccTLD is listed, you're good and the tool will route automatically. If not, RDAP isn't available for that TLD and you'll need to use the registry's own WHOIS service or web form. .in, .uk, .br, .au and several others have RDAP support now, but you'll still find ccTLDs where the only option is the legacy WHOIS endpoint or the registry's web-based lookup page.

It's a solid public starting point — the registration events, status codes, and nameservers are all authoritative. But for serious due diligence — buying a domain, M&A, legal disputes — never stop at RDAP. Cross-check with WHOIS history (DomainTools), backlink profile (Ahrefs), traffic data (SimilarWeb), and Wayback Machine for content history. RDAP tells you what the domain is right now, not what it was, where its links came from, or whether it has a Google penalty hidden in the past.