An email validation system receives an email validation request from a requestor to validate an email, the email validation request indicating at least a sender domain indicating a domain of the sender of the email. The email validation system determines whether the sender domain is in a whitelist of known domains, wherein a known domain is a domain that is linked to an organization whose provenance is known, such that it can be linked to an identifiable entity in the real world. The email validation system generates, in response to determining that the sender domain is not in the list of known domains, a message indicating that the email is not valid. The email validation system generates, in response to determining that the sender domain is in the list of known domains, the message indicating that the email is valid, and transmits the message to the requestor.