Bulk email domain registrar lookup: who holds the domain behind each address?
In short: Paste email addresses and see each domain's registrar, registration and expiry dates, DNS host and mail provider from the registry's RDAP record, with a CSV of every row. Limit: Reads the domain, never the mailbox: a registered domain says nothing about a particular address.
A bulk email domain registrar lookup reads the domain after the @ in each address and asks its registry who holds it. Paste up to 100 unique domains a run, or 500 after a free Google sign-in, and every address gets a row with registrar, expiry, DNS host and mail provider. It checks the domain, not the mailbox. Download the CSV.
Checking the registrars behind a lead list? A held domain doesn't mean a live mailbox.
Price: this tool is free. Checking a whole email list is from $9/mo, and the first 100 checks are free with Google, no card. Check your list free nowSee pricing
Sample result
tom@globex.example is at a domain with a registrar, an expiry date and its DNS at another company.
- Address
- tom@globex.example
- Registrar
- Example Registrar, Inc.
- Expires
- 4 Mar 2027
What this means for you
The record names who holds the domain, not who owns the mailbox. A passed expiry date can be a renewal grace period.
- Registrar and dates per address
- DNS host and mail provider
- No-record domains flagged
- CSV out, nothing emailed
- RDAP
- Registrar
- CSV
By SimpleVerifier Team · Last updated
Got a list with addresses at domains that may have lapsed?
- Paste it above to see each domain's registrar, expiry and DNS host, with a CSV of every row.
- Upload or paste it at /verify. Every address gets a live mailbox check, and the first 100 email checks are free with a Google sign-in, no card.
How do I find the registrar for every email address on a list?
- Paste email addresses, one per line, or upload a CSV. Addresses are found anywhere in the text, so a whole export works.
- Press Find registrars. Only the unique domains are sent, never the mailbox names, 10 a request: each registry is asked for its RDAP record and the NS and MX records are read from public DNS. No mail is sent.
- Read each row: Registered with the registrar's name, Past its expiry date, No registry record, or a note that the registry gives no registrar.
- Filter to the flagged addresses, download the CSV, and hand the rest to the mailbox check.
Example
- You enter
- Four addresses:
jane@acme.example(registered, expiry ahead),tom@globex.example(expiry date already passed),ana@initech.example(no registry record, no nameservers) andbo@umbrella.example(an ending whose registry publishes no RDAP). - You get
- jane: Registered, with registrar, dates, DNS host and mail provider in the CSV. tom: Past its expiry date. ana: No registry record. bo: Registry gives no registrar. Download the CSV.
- Limits
- Up to 100 unique domains a run without an account and 500 when signed in with Google. 10 domains a request; registry records, NS and MX only, nothing is emailed.
Where does the registrar come from?
From the registry. Every generic top-level domain's registry runs RDAP, the structured successor to WHOIS, and its record names the registrar the domain is held with (ICANN). The tool finds the right registry in IANA's RDAP bootstrap file and reads the registrar, registration date and expiry from it.
Some country endings publish no RDAP, so their registrar shows as not given. The row says so instead of guessing.
Why look at registrars on an email list?
A domain with no registry record and no nameservers takes no mail, so every address at it will bounce. A domain past its expiry date may be in a renewal grace period or may be about to lapse. Both are cheap to find by domain, because a list of thousands of addresses has far fewer unique domains.
The DNS host and mail provider columns tell you where the domain's records are edited and who receives its mail, which helps when you are cleaning a list that came from several sources.
What do you do with the flagged rows?
Take No registry record rows off the send list. Recheck Past its expiry date rows later, since many renew. For the full registration record, including status codes and DNSSEC, use the bulk WHOIS lookup.
Before you email anyone on the rest, verify the addresses.
Who uses this tool, and for what?
- Marketers
- Drop addresses at domains with no registry record before an import.
- Sales teams
- Spot lead-list companies whose domain is past its expiry date.
- Agencies
- See who registered and who hosts the DNS for every client-list domain.
- Developers
- Triage a signup export by registrar and mail provider.
What can’t this tool tell you?
- Reads the domain, never the mailbox: a registered domain says nothing about a particular address.
- Country endings without RDAP show no registrar; a registry that doesn't answer in time shows as not answering.
- A registry answer of no record is not proof a name is free; the row says when the name still has DNS.
- Up to 100 unique domains a run without an account, 500 signed in. Subdomains are reduced to the registered name.
Common questions
- How do I find the registrar for every email address on a list?
- Paste the list into a bulk email domain registrar lookup like this one. It reads each address's domain and asks the registry for the registrar, registration date and expiry date.
- Is this bulk email domain registrar lookup free?
- Yes. It is a free tool: up to 100 unique domains a run with no account, and up to 500 a run when you sign in with Google, with no card.
- Does it tell me whether the mailbox exists?
- No. It checks the domain, not the mailbox. A registered domain can still hold a closed mailbox.
- Why does a row say the registry gives no registrar?
- Some country-code registries publish no RDAP service. For those, the registrar is shown as not given rather than guessed.
- Does a passed expiry date mean the domain has lapsed?
- Not always. It can be a renewal grace period or a stale record, so recheck those rows later.
- Does it send an email to the domain?
- No. It reads registry records and public DNS. It never connects to a mail server.
Sources
A tidy list can still be full of dead addresses.
Extracting, deduplicating and syntax checks all work on the text of an address. None of them can tell whether the mailbox exists. Only the server that hosts it can answer that, through an SMTP check, and that is what the paid product does.
- Upload the cleaned file as it is: CSVs up to 100,000 rows
- A real SMTP mailbox check on every row, with catch-all detection
- Small list? Starter at $9/mo covers 2,500 emails a month, cancel anytime
Plans from $9 a month, cancel anytime, no contract. Sign in with Google and your first 100 email checks are free, no card. The free tools stay free either way.