Email domain lookup

An email domain lookup turns the part after the @ into facts about the organization behind it. Enter an address or a domain above to find the company website from an email address, see which provider hosts its mailboxes, check whether it publishes SPF and DMARC, and tell a company domain from a free or disposable one. It reads public DNS records and our own domain lists; nothing about the person who uses the address.

What the email domain lookup shows

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The SPF and DMARC lines say whether a record exists. For a full check of the record, the lookup links to the SPF checker and the DMARC checker; for every MX record with its priority and TTL, use the MX lookup.

How to find a company website from an email address

1. Take the domain. In jane.doe@sales.example.org, everything after the @ is the domain: sales.example.org. A subdomain belongs to the domain at its end, so the organization is example.org.
2. Rule out free and disposable providers. An address at gmail.com, outlook.com or yahoo.com belongs to an individual account; the website there is the provider’s. The lookup flags these with our lists.
3. Check that a website exists. A domain used only for email often has no address records at all. The lookup checks the A and AAAA records of both example.org and www.example.org and links to whichever has them; it doesn’t open the site.
4. Read the website. The About, Contact or legal notice page names the company. A company can also run its website on a different domain than its email, for example after a rebrand.

To find an address for a person at a company, rather than the company behind an address, see how to find someone’s email address.

How it works

The lookup runs in your browser. It sends the domain name, never the full address, to Cloudflare’s public DNS-over-HTTPS resolver and asks for the MX records of the domain, the A and AAAA records of the domain and its www. host, its SPF record (TXT) and its DMARC record (TXT at _dmarc.). When a subdomain has no DMARC record of its own, the lookup reads the one of the organizational domain. The free-webmail, disposable and brand checks compare the domain with lists this site publishes, so they need no request to anyone else. The website is never opened.

Email host lookup by MX record

Mail providers give their customers fixed MX values, so the hostname in the MX record shows who receives the mail. These are the patterns the lookup recognizes, each taken from the provider’s own setup instructions:

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Any other host in google.com, such as the MX of gmail.com itself, shows as Google. A provider that isn’t in the table, or a regional variant its documentation doesn’t list, shows as “not a provider we recognize” together with the raw MX hosts. Sources checked October 10, 2026. Server settings for more than 100 providers are on the email server settings pages.

You can run the same queries on the command line:

dig MX example.org +short
dig A www.example.org +short
dig TXT _dmarc.example.org +short

What it can’t tell you

• Who uses the address. Every address on a domain gets the same answer. The lookup doesn’t search for people and has no data about them.
• Whether the mailbox exists. A domain with working MX records can still reject jane@ because no such mailbox exists. Only a check with the mail server answers that.
• What the website is. An A record means the domain points to a server, not that a company website is there: it can be a parked domain, a redirect or a hosting placeholder. We don’t open the page; you should before relying on it.
• Which company, for most domains. The brand check covers about 175 large brands that phishing often imitates. For any other domain, the website is the place to find the company name.
• Where the mailboxes are behind a gateway. With Mimecast, Proofpoint or Barracuda in the MX records, the mailboxes can be at any provider. A company can also move providers at any time; the lookup shows today’s records.
• Whether a sender is honest. SPF and DMARC protect the domain owner against forgery; a scammer’s own domain can publish both. For a suspicious message, use the scam email checker.

Validate the address

A domain that looks right says nothing about the mailbox. The free email checker asks the receiving server whether the mailbox exists, without sending an email, and flags disposable, role and free addresses. For addresses in your own code, the email validation API returns these checks as JSON, including the fields domain, mx_found, free and disposable.