Everything you need to know about email verification.
Email verification checks if an email address is valid and can receive messages. We connect to the mail server using SMTP protocol to verify deliverability without sending an actual email.
Valid: Email exists and can receive messages.
Invalid: Email doesn't exist or will bounce.
Unknown: Server restrictions prevented verification.
A catch-all domain accepts emails to any address, even non-existent ones. For these domains, we can confirm the domain is valid but not the specific mailbox.