This validation will hurt the IP?

[imcda]

I know something like https://github.com/hbattat/verifyEmail can use PHP to validate the email.

but use it oftenly will cause the IP blocked, so the amount is limited.

I want to know Flanker will hurt the IP reputation or not?

Thank you

[horkhe]

Unlike the tool you mentioned Flanker does not make requests to MX servers to verify that such mailbox exists there. Therefore it cannot hurt your IP reputation. Flanker only checks the email address grammar, ESP specific grammar for a selected list of ESPs, and presence of MX records for the domain part of the email address.