Domain lookup intro
The complete domain lookup guide
Domain lookup is the standard way to inspect a domain's registration data. This guide starts from the definition, then walks through why you need to run a domain lookup, which protocols are involved, how to choose a domain lookup tool, and the privacy and legal considerations you should keep in mind.
What is a domain lookup?
Domain lookup is the umbrella term for any query that retrieves a domain's registration data. When you buy a domain from a registrar, the registrar records the registrar name, creation date, expiry, nameservers, DNSSEC status, and domain-status flags in the TLD registry's database. A domain lookup pulls that data back from the authoritative registry or registrar servers. In practice, "domain lookup" can mean three things: (1) checking whether a domain is registered, who the registrar is, and when it expires — the most common WHOIS lookup; (2) checking which IPs and mail servers the domain resolves to — a DNS lookup; (3) reviewing the historical change log — past nameservers or registrar changes. This site integrates WHOIS, RDAP, and DNS so a single domain lookup returns a complete picture.
Why do you need a domain lookup?
Common scenarios: (1) before registering a new domain, a domain lookup confirms whether it is taken and when it might be released; (2) when buying a domain, a domain lookup verifies the registrar, registrant class, and transfer lock; (3) when troubleshooting a site, a domain lookup confirms the nameservers point to your DNS provider; (4) for security research, a domain lookup highlights anomalies in registration data and timing — useful for anti-phishing investigations; (5) for routine audits, a domain lookup helps track upcoming expiry to prevent accidental loss. For IT, security analysts, domain investors, and marketers, domain lookup is a daily workflow primitive.
Three protocols behind domain lookup: WHOIS, RDAP, DNS
Although domain lookup looks like a single action, three protocols power it: (1) WHOIS is a plain-text protocol from RFC 812 (1982), reachable on TCP port 43, returning human-readable text. (2) RDAP (Registration Data Access Protocol), defined in RFC 7480–7484, is the modern successor — HTTPS, JSON, consistent across TLDs. Every ICANN gTLD now mandates RDAP, and most major ccTLDs support it. (3) DNS lookups operate on the resolution layer — which IPs, mail servers, or TXT records a domain points to. WHOIS/RDAP cover the registration management layer; DNS covers resolution. This site detects each TLD's capability, prefers RDAP, falls back to WHOIS when necessary, and shows DNS records side by side — a one-shot domain lookup.
How to choose a domain lookup tool?
Tools fall into three categories: (1) command-line — whois and dig on Unix are fast but need expertise, and non-RDAP TLDs require manual upstream servers; (2) web tools like whois.net.tw, whois.com, who.is — type a domain and read a structured result, ideal for most users; (3) API services — REST endpoints and batch lookups, suited for automation. Selection criteria: does it cover WHOIS, RDAP, and DNS? Does it hit authoritative servers (not stale caches)? Does it cover every common TLD? Is it free with no signup wall? Is the output easy to read? This site meets all of the above and ships in Traditional Chinese, Simplified Chinese, and English.
Privacy and legal aspects of domain lookup
Since ICANN's 2018 post-GDPR policy, personally identifying fields in domain lookup results (registrant name, email, phone) are typically masked as REDACTED FOR PRIVACY by the registrar. That means a domain lookup cannot directly reveal natural-person registrant data, although corporate registrations usually remain visible. For law enforcement or vetted security research, you can request Tiered Access through the registrar. Domain lookup itself is legal and public, but using the results for unsolicited mail, harassment, or attacks violates data-protection and computer-crime laws. This site caches lookup results only briefly and never sells or forwards the data.
Run a domain lookup now
Head to the home page, type any domain, and see the full domain lookup result.
Go to the home pageDomain lookup FAQ
Is domain lookup the same as WHOIS lookup?
Not exactly. "Domain lookup" is the umbrella term covering WHOIS, RDAP, DNS, and more. "WHOIS lookup" specifically refers to data fetched via the WHOIS protocol (TCP port 43). This site integrates all three, so a single domain lookup returns WHOIS/RDAP/DNS data together.
How is domain lookup different from DNS lookup?
Domain lookup (WHOIS/RDAP) returns registration-management data — owner, registrar, expiry. DNS lookup returns resolution data — IPs, mail servers, TXT records. The first comes from registries and registrars; the second from authoritative nameservers. This site shows both for any domain.
Do I need an account to run a domain lookup?
No. Type a domain and you see the full result immediately — no signup, no payment, no daily quota. Some third-party services gate the full data behind paid plans; this site does not.
Why doesn't the domain lookup show the registrant's name or contact info?
Since ICANN's 2018 GDPR policy, natural-person registrant fields are masked as REDACTED FOR PRIVACY by the registrar. That redaction is a regulatory requirement, not something this site hides. Corporate registrations typically remain visible.
Which TLDs are supported?
All common TLDs — .com, .net, .org, .tw, .jp, .uk, .de, .cn, .hk, .io, .ai, .dev and more. The backend resolves each TLD to its WHOIS or RDAP server via IANA bootstrap, with no manual configuration.