Findymail

Findymail performs actual SMTP connections to verify whether a mailbox exists, rather than relying on pattern matching or pre-built databases. The real-time validation includes MX record checks to confirm mail servers are active and bounce testing to detect undeliverable addresses before you send.

Good for campaigns where you need high confidence that an email address is actually live and monitored. Direct SMTP validation costs more per check than database lookups, but it gives the strongest possible signal for list hygiene and helps protect your sender reputation from bouncing to bad addresses.