EmailResolver allows you to validate email addresses much more effectively than simple syntax checking. It signficantly improves the quality of email addresses that you collect and compile. EmailResolver achieves this in 5 steps: Checks the syntax of the email address; Looks up the domain of the address to see if it exists; Retrieves the mailservers that are valid for this address; Queries the mailservers to see if the email can be verified, and if not; Sends a proto-message to the mailserver to see if the mailserver would accept this email address. Together, EmailResolver and PasswordCheck make the job of accepting valid new members a breeze.