Free email verification API

This will work really well at small scale. As you start to make large volumes of queries against major email service providers, they will start blocking you. It then becomes a cat and mouse game as you move IP address is constantly to try to avoid detection. The only long-term strategy for recipient validation that actually works is to partner with somebody who sends a great deal of legitimate email, and mine their logs.

Source: My company runs a large scale email sending service. Inquire within.

Can this replace BriteVerify or Kickbox? It looks like this would have trouble scaling based on the comments. Is that at hundreds, thousands or millions of emails per month?

Are all SMTP servers set to complain if the RCPT TO address doesn't exist?

nice work man