Bulk email website host checker: which platform hosts each address's website?
In short: Paste email addresses and see which host serves each domain's website, any CDN in front of it, the DNS host and the mail provider, with the evidence in the CSV. Limit: Reads the domain, never the mailbox: a host says nothing about a particular address.
A bulk email website host checker reads the domain after the @ in each address and works out which platform serves its website, from CNAME and A records and the headers of the home page's first response. Paste up to 100 unique domains a run, or 500 signed in. It checks the domain, not the mailbox. Download the CSV.
Know where their sites live? A hosted site doesn't mean the mailbox works.
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 whose website is served by a hosting platform behind a CDN.
- Address
- tom@globex.example
- Evidence
- www CNAME sites.hosting.example
- CDN
- Example CDN
What this means for you
The host is read from DNS records and headers, so it is the most likely platform, not a certainty.
- Host named with its evidence
- CDN shown on its own
- DNS host and mail provider
- CSV out, nothing emailed
- Host
- CDN
- CSV
By SimpleVerifier Team · Last updated
Got a list of company addresses and want to see where their sites live?
- Paste it above to see the host, CDN, DNS host and mail provider behind each address's domain, 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 which host runs the websites on an email 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 website hosts. Only the unique domains are sent, never the mailbox names, 10 a request: CNAME, A, NS and MX records are read from DNS and the home page is requested once for its headers. No mail is sent.
- Read each row: the host's name, Behind a CDN, Host not recognised, No website or Domain doesn't resolve, with the evidence that matched.
- Filter, download the CSV with the host, CDN, DNS host, mail provider and HTTP status, and hand the rest to the mailbox check.
Example
- You enter
- Four addresses:
jane@acme.example(a CNAME to a hosting platform),tom@globex.example(a site behind a CDN),ana@initech.example(a company's own server) andbo@umbrella.example(no address record). - You get
- jane: the platform's name, with the CNAME that matched. tom: Behind the CDN's name. ana: Host not recognised. bo: Domain doesn't resolve, with whether it has mail. 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; DNS plus one request to each home page for its headers.
How is the host worked out?
From three sources: the domain's CNAME and A records, the headers of one request to the home page (the page body is not read), and its NS and MX records. A record that points at a known platform, or a header such as server, names the host, and the row shows the exact record or header that matched.
A CDN in front of a site can hide where it is really hosted. The tool names the CDN in its own column and says so, rather than naming a host it can't see.
Why check hosts on an email list?
A domain with no website at all, or one that doesn't resolve, can be a company that has stopped trading, or a domain used only for mail. The mail provider column shows which. Hosts also let you group a list by platform before a campaign aimed at, say, shop owners on one platform.
To read the same signals for bare domains, use the website host checker.
What do you do with the result?
Take Domain doesn't resolve rows with no mail server off the send list. Treat Host not recognised as unknown, not as a problem. To see which sites are up at all, use the bulk email website status checker.
Before you email anyone on the rest, verify the addresses.
Who uses this tool, and for what?
- Sales teams
- Group a lead list by the platform each company's site runs on.
- Agencies
- See where each client-list domain is hosted and who runs its DNS and mail.
- Marketers
- Drop addresses at domains that no longer resolve before an import.
- Developers
- Triage a signup export by host and mail provider.
What can’t this tool tell you?
- Reads the domain, never the mailbox: a host says nothing about a particular address.
- The host is the most likely platform from DNS records and headers, not a certainty; a CDN can hide it.
- Only the home page's first response is requested, once per domain, from our server; its body is not read.
- Up to 100 unique domains a run without an account, 500 signed in. Free providers such as gmail.com are looked up like any domain.
Common questions
- How do I find which host runs the websites on an email list?
- Paste the list into a bulk email website host checker like this one. It reads each address's domain and works out the host from DNS records and the home page's response headers.
- Is this bulk email website host checker 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 live website can sit above a closed mailbox.
- Why does a row say Host not recognised?
- The site answered but its records and headers match no platform we know, which is typical of a company's own servers.
- Can a CDN hide the real host?
- Yes. When a CDN is in front of a site the real host is not visible, so the row names the CDN instead.
- Does it send an email to the domain?
- No. It reads DNS and requests each home page once for its headers. 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.