Beijing Express Maillist Verify is application software that can accurately verify the authenticity of email addresses from your contact or mailing list. It checks all the email addresses in your mailing list and notify you about all the dead or wrong email addresses. It is used by those people who have a large mailing list and need to be in contact with them necessarily. So with the help of this application they come to know about the mailing addresses that are dead and can find other ways to contact them. Here the mailing server SMTP tries to connect with the destined email address and if it is unsuccessful in doing so it notifies the user. Most of the mailing tools mail the substance to the recipients and if the email address of recipient is fake they later on send it back to the sender with failure message but Beijing Express check verifies the email address first and then send the email only if the email address is correct and if the email address is incorrect it notifies the sender in the beginning and saving loss of energy and time of the user.