Donor lists age quickly; re-engagement and sunset policies protect reputation.
What email bounce handling is#
Bounce handling is the automated processing of delivery failure notices (DSNs) to classify hard versus soft bounces and suppress addresses accordingly.
Why it matters#
Repeatedly sending to invalid addresses is one of the strongest negative reputation signals providers track.
Implementation plan for nonprofits#
- Parse DSN codes: 5.1.x means the address does not exist (hard); 4.x.x means temporary (soft).
- Suppress hard bounces after one failure and soft bounces after three.
- Route bounce notifications to a monitored mailbox or webhook.
- Review bounce reasons weekly for patterns like 'blocked' that indicate reputation issues.
Priorities specific to nonprofits#
Donor lists age quickly; re-engagement and sunset policies protect reputation. Weight your effort toward the steps above that address this constraint first, and measure with metrics that match how nonprofits generate value from email.
Common mistakes#
- Treating 'mailbox full' as a hard bounce and losing valid contacts.
- Ignoring 'blocked by policy' bounces that signal a blocklist or DMARC failure.
Frequently asked questions#
What is the difference between a hard and soft bounce?
Hard bounces are permanent failures (bad address). Soft bounces are temporary (full mailbox, server down). Suppress hard immediately.