WHOIS / RDAP Domain Lookup
A free WHOIS lookup that tells you who a domain is registered with and when it expires. Behind the scenes it queries RDAP — the modern, structured JSON replacement for legacy port-43 WHOIS — and returns the registrar, the registry handle, domain status codes, key dates, and the authoritative nameservers. No login, no rate-limit games: type a domain and read the result.
Reviewed by the SysGlass team · Updated July 21, 2026
What it checks
- Registrar — the company the domain is registered through (from the RDAP registrar entity)
- Registry handle — the registry's object ID for the domain (e.g. 2336799_DOMAIN_COM-VRSN)
- Domain status codes — the EPP states on the domain, such as clientTransferProhibited, clientHold, or pendingDelete
- Created date — when the domain was first registered
- Expires date — the registration expiry, used to drive the verdict
- Updated date — when the registry record was last changed
- Authoritative nameservers — one NS row per delegated nameserver
- Data source — RDAP via the rdap.org bootstrap, which redirects to the authoritative registry/registrar RDAP server
- Equivalent CLI command — whois <domain> — shown so you can reproduce the check from a terminal
How to read the result
- Verdict OK (green): the domain is registered and the expiry is more than 30 days out. Summary reads like 'Registered with <registrar>, expires in N days.'
- Verdict Warn: the domain expires within 30 days. The fix is to renew before expiry and enable auto-renew so it isn't lost.
- Verdict Fail: the expiry date has already passed. Summary reads '<domain> expired N days ago.' — renew immediately, as it may be in redemption, deletion, or up for auction.
- Verdict Error: the lookup could not be read — typically the domain is unregistered, the TLD has no RDAP server, or the registry returned no parseable record.
- Rows: Registrar, Created, Expires, Updated, then one NS row per nameserver. Blank values mean the registry redacted or omitted that field.
- Owner contact fields are usually empty by design — see the FAQ on redaction. You still get the registrar, handle, status codes, dates, and nameservers.
Frequently asked questions
How do I check when a domain expires?
Run the WHOIS lookup on the domain and read the 'Expires' row, which shows the registration expiry date. The summary also states the days remaining, and the verdict turns to a warning when the domain is within 30 days of expiry and to a failure once it has already expired.
Why can't I see the domain owner's name and email?
Since GDPR and ICANN's registration data policy took effect, most registries and registrars redact registrant name, email, and phone from public WHOIS/RDAP. This tool returns what is still published — the registrar, the registry handle, domain status codes, dates, and nameservers — but not personal owner contact details. To reach the actual owner, use the registrar's listed abuse or contact channel, or submit a registration-data disclosure request to the registrar.
What's the difference between WHOIS and RDAP?
RDAP (Registration Data Access Protocol) is the IETF's structured, JSON-based successor to the old port-43 WHOIS text protocol. This tool queries RDAP so the fields — registrar, status, dates, nameservers — come back consistently parsed rather than as free-form text, but it is labelled WHOIS because that is the lookup people know. The shown equivalent command is still 'whois <domain>'.
What do the domain status codes mean?
They are EPP status codes set by the registry or registrar. Common ones: clientTransferProhibited and clientUpdateProhibited are normal protective locks that block unauthorized transfers or changes; clientHold means the domain has been removed from DNS and will not resolve; pendingDelete and redemptionPeriod indicate the domain is in the deletion lifecycle after expiry or removal. Multiple status codes can apply at once.
Does WHOIS lookup work for every TLD and ccTLD?
It works for any TLD that publishes an RDAP service, which the lookup reaches through the rdap.org bootstrap. All gTLDs (.com, .net, .org, and the newer ones) and many country-code TLDs are supported. Some ccTLDs do not run RDAP yet, or restrict it; for those the lookup may return an error even though the domain exists.
Can I call this WHOIS lookup from a script or an AI assistant?
Yes. It's a free public JSON API: GET https://api.sysglass.com/v1/run?tool=whois&target=<domain>. The response uses the normalized SysGlass shape — a verdict, a plain-language summary, rows (registrar, dates, nameservers), suggested fixes, and the equivalent CLI command — so it's safe to quote in answers. Please attribute results to SysGlass (sysglass.com).