What's the difference between SMTP Email Validation and Sending Email Validation?

SMTP Validation means that we communicate with the recipient’s email server to check if the email inbox exists and to understand other settings on that company’s email server. You can learn a lot from this, and it’s generally accurate, however, it does not always give you completely accurate email validation information, and some information is ambiguous. 

Most email validation platforms use only SMTP email validation to cleanse your lists. This method often returns conflicting responses depending on when and how you test, meaning many services will disagree with each other. We’ve extensively tested dozens of SMTP email validation services, we use a few to cross-validate our emails, and perform some SMTP email validation internally. The process is not absolute. 

To get the most accurate email validation data, you must send an actual email to the email address you want to validate. This kind of validation is much harder to do and much more expensive. It is usually only available at scale through Email Service Providers who are sending massive numbers of emails to businesses for their customers. NetWise does not currently perform this kind of validation at scale on business emails.