SeeTheStackSeeTheStackA domain's MX records say which servers accept its mail, and every mail host uses its own: Google Workspace's end in google.com, Microsoft 365's in mail.protection.outlook.com, Zoho's in zoho.com. We look up the MX records and match them against the hosts we know, then read the SPF record and DKIM keys for the services allowed to send mail as the domain, such as SendGrid, Amazon SES or Mailgun.
Some companies route mail through a security gateway like Mimecast or Proofpoint first. The MX records then name the gateway, not the mailbox, so we say so and look for the mailbox host in the SPF record instead.
Limits: this reads public DNS only. A domain with no MX records doesn't receive mail at its own address, and one that runs its own mail server shows up as its own hostnames rather than a provider.
Enter the domain above. We look up its MX records, which name the servers that receive its mail, and match them to the provider that runs them.
A DNS record that says which mail servers accept email for a domain, each with a priority. Senders try the lowest number first.
Yes. Email lives in DNS, so we only need the domain, not a working homepage.
Yes. There's no sign-up and no limit on lookups.
Share of the 11,986 scanned sites whose DNS we could match to a provider.
