Check if an email address is valid for sending emails

A DNS lookup can report mail-related records for an email address’s domain. It cannot prove that a mailbox exists or that a message will be delivered. This example reports DNS evidence without claiming address validity.

The Google Public DNS JSON API accepts a domain name and record type. Request MX directly: an ANY query need not return every record type. The JSON Status field is the DNS response code, separate from the HTTP response status.

function checkEmail(email) {
  _$(email, "email").check(v => isString(v) && /^[^\s@]+@[^\s@]+$/.test(v)).$_();
  var domain = email.substring(email.lastIndexOf("@") + 1);
  var response = $rest({ uriQuery: true, throwExceptions: true, timeout: 5000 })
    .get("https://dns.google/resolve", { name: domain, type: "MX" });
  var records = (response.Answer || []).filter(record => record.type === 15);
  return {
    domain: domain,
    dnsStatus: response.Status,
    mxRecords: records.map(record => record.data)
  };
}

Call checkEmail("person@example.org") with the address you want to inspect. Results depend on current DNS data; transport errors throw. An empty record list alone is not proof that the domain is nonexistent or that all mail delivery is impossible. The syntax check is deliberately basic and is not a complete email-address parser.

For direct DNS queries through OpenAF, see ow.net.getDNS.