Email provider lookup
Enter a domain to see who hosts its mailboxes and which services are allowed to send email for it, read from its MX and SPF records.
How to read the result
Mailboxes hosted by comes from the MX records: where mail to people at the domain goes. Allowed to send comes from the SPF record: services the domain authorises to send as it. Includes that match no known service are listed as they are.
Both records are shown in full below, with any problems in them. For the complete picture with DMARC and blocklists, run the domain health check.
Questions
- How do you know which email provider a domain uses?
- From public DNS. MX records name the servers that receive mail, and those hostnames belong to the provider (aspmx.l.google.com is Google Workspace). SPF includes name the services allowed to send (include:amazonses.com is Amazon SES).
- Why can the mailbox provider and the sending services differ?
- Because most companies use both: people's mailboxes at Google or Microsoft, and product email (receipts, password resets) through a sending service like SES, Resend or Postmark, often from a subdomain.
- Why is a provider not recognised?
- The lookup matches known hostnames. A self-hosted mail server, a small provider, or a security gateway in front of the mailboxes (Mimecast, Proofpoint) shows up under its own name or not at all. The raw records are under the summary.
- Does it look up DKIM?
- No: DKIM keys sit under a selector (like google._domainkey) that is not listed in DNS. The DKIM checker tries the common selectors, or reads the one you give it.
More free tools
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DKIM checker
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