How to Find Out Who a Domain Is Registered With

A domain's registrar is listed in its registry's registration record, so look it up there. Enter the domain in the domain registrar lookup: it reads the RDAP record for the registrar and expiry date, the NS records for the DNS host, and the MX records for the email provider. You can check one domain or paste a list.

Find a domain's registrar now →

Find the registrar with the lookup tool

1. Open the domain registrar lookup.
2. Enter a domain, or paste a list, one per line. Emails, URLs and subdomains are reduced to the registered name, so mail.acme.co.uk is looked up as acme.co.uk.
3. Press Find registrar and DNS host. The domain's registry is asked for its RDAP record, and its NS and MX records are read from public DNS.
4. Read three answers: where the domain is registered, where to edit its DNS records, and who runs its email.
5. For a list, download everything as CSV. Up to 100 domains a run, or 500 after a free Google sign-in.

Find the registrar by hand

On macOS or Linux, whois follows the registry's referral and prints the record:

whois google.com | grep -i "registrar:"
#   Registrar: MarkMonitor Inc.

Or ask the registry's RDAP server directly. Each TLD's server is listed in IANA's RDAP bootstrap file; for .com it's Verisign:

curl -s https://rdap.verisign.com/com/v1/domain/google.com \
  | jq -r '.entities[] | select(.roles | index("registrar")) | .vcardArray[1][] | select(.[0]=="fn") | .[3]'
# MarkMonitor Inc.

The registrar appears as an entity with the registrar role. The ICANN RDAP page (read 8 November 2026) says RDAP "was created as the replacement for the WHOIS protocol" and that, since 28 January 2025, gTLD registries and registrars "are no longer required to provide WHOIS services (except for .com, .name, and .post)". So whois still answers for many TLDs, but RDAP is the record to rely on for gTLDs.

Registrar vs DNS host vs email provider

These are three different jobs, often at three companies:

• Registrar: where the domain is paid for and renewed. Transfers and renewals happen here.
• DNS host: whoever runs the nameservers in the NS records. MX, SPF, DKIM and DMARC records are edited here. See where to edit a domain's DNS.
• Email provider: whoever the MX records point to, such as Google Workspace or Microsoft 365.

Why the owner isn't shown

Public registration records usually redact the registrant's personal contact details. The registrar is still listed, and most registrars offer a way to contact the registrant through them. If you need the owner, that's the route, not the lookup.

Next step: check the addresses on those domains

If you're auditing domains before a campaign, the useful question after "who runs it" is "will mail to it bounce". Upload your CSV at /verify: each address gets a live mailbox check without sending a message. The first 100 checks are free with a Google sign-in, no card.

Pro, $39 a month: Unlimited email verification.* Never metered, never cut off. See pricing.

*Fair use: the first 100,000 checks a month at full speed, then slower, never cut off.

More: bulk WHOIS lookup for a list of domains, find when a list of domains expires, cold email domain setup.