Process bounces and spam complaints
Connect bounce and complaint sources so permanent failures and abuse reports become durable send protections without treating every temporary bounce as permanent.
Bounce and complaint sources
K2Mailer can process delivery-failure and complaint events from configured mailbox handlers and supported provider callback routes. Provider callbacks are usually preferable when the sending provider offers reliable event delivery, while mailbox parsing can support other setups.
Hard and soft bounces are not the same
- Hard bounce
- A permanent delivery failure, such as an invalid or non-existent mailbox. Hard-bounce evidence is treated as a durable delivery protection and can block the address across tenant campaigns.
- Soft / transient bounce
- A temporary failure such as a full mailbox or transient provider condition. It should not be described as permanent consent loss merely because one temporary delivery attempt failed.
- Spam complaint
- A recipient abuse report. Complaint protection is more restrictive than an ordinary list subscription state and should not be bypassed by resubscribing a membership.
Why processing protects sender reputation
Continuing to send to permanently invalid mailboxes or known complainants increases avoidable reputation risk. K2Mailer therefore checks current bounce, complaint, and suppression state again in the live sending path rather than trusting only the list membership selected when the campaign was scheduled.
These safeguards work with authenticated sending domains, preflight, list hygiene, and paced delivery. None of them can guarantee inbox placement, but together they reduce preventable operational mistakes.
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