The SMTP check is at the core of every email validation service. What it does is simulate a partial email delivery to identify if a mailbox is available. Here is a simple SMTP email validation at work:
<< 220 extmail.emailserver.com ESMTP Service ready
>> HELO myemailserver.com
<< 250 extmail.emailserver.com
>> MAIL FROM:
<< 250 MAIL FROM: OK
>> RCPT TO:
<< 550 recipient rejected. Recipient does not exist. IB603a
Look simple? Well there are another 3-4 proprietary steps we take, depending on the server we encounter. Would you believe that even how the core component of an email validator varies vastly between competitors?
Our superior understanding of the SMTP protocol
means we can make sure you are getting the best delivery rate you could hope for, without compromising your sender score or other quality metrics.