@rp how can i attach email address checker before sending out verification emails?

hey @bian what kind of a checker are you talking about? You could for example override the sendEmail function in emailverification recipe to do your check. Or you could override the email verification POST API to do the check.

email bounce checker to preventing sending emails to non-existing emails which has bad effect on ROI.

right. So the best place to add that would be in the sendEmail function override