How to Find Which Hosts Run the Websites Behind an Email List

To find which host runs the website behind each address on a list, read the domain's CNAME and A records and the headers of its home page. The bulk email website host checker does this for every address in a pasted list or CSV and gives each one a row: the host's name, Behind a CDN, Host not recognised, No website or Domain doesn't resolve.

The check reads the domain, not the mailbox.

Why look at hosts on an email list

Hosts let you group a list by platform before a campaign aimed at, say, shop owners on one platform. They also show domains with no website: a domain that doesn't resolve and has no mail server takes no mail, so every address at it bounces. A list of thousands of addresses has far fewer unique domains, so checking by domain is cheap.

The by-hand way

1. Take the domain after the @, for example acme.example from sam@acme.example.
2. Look up its CNAME and A records with a bulk DNS lookup.
3. Request its home page and read the response headers, such as server.
4. Match what you find to a platform, and repeat for every unique domain.

The single-domain version of this is explained in find which company hosts a website.

Step 1: paste the addresses

Paste addresses one per line, or upload a CSV. Only the unique domains are sent, never the mailbox names, 10 a request.

Step 2: run the check

Press Find website hosts. DNS records are read and the home page is requested once for its headers; the page body is not read. No mail is sent.

Step 3: read the result

Result	What it means
A platform's name	Most likely host, with the record or header that matched
Behind a CDN	A CDN is in front, so the real host is hidden
Host not recognised	The site answered but matches no platform we know
No website	The domain resolves but nothing answered on its home page
Domain doesn't resolve	No address record; the row says whether it has mail

The CSV carries the host, CDN, DNS host, mail provider, HTTP status and redirect target beside each address.

What this check cannot do

• It checks the domain, not the mailbox.
• The host is the most likely platform, not a certainty.
• Only the home page's first response is requested, once per domain.
• Up to 100 unique domains a run without an account, 500 signed in.

For bare domains use the website host checker.

Next: the rest of the list

For the addresses that remain, use the verify page: the first 100 checks are free with a Google sign-in, no card.

Try it now

Paste your list into the bulk email website host checker at simpleverifier.com.