Performance Marketing
What is Hard Bounce?
A Hard Bounce is an email that permanently fails to deliver — typically because the address doesn’t exist, the domain is invalid, or the recipient’s server has blocked delivery outright — as opposed to a temporary soft bounce.
Who Is It For?
Hard bounces are monitored by whoever manages email infrastructure, since letting them accumulate can damage sender reputation for the whole team.
How Is It Used?
Tracking hard bounces is used to protect email deliverability, since sending repeatedly to invalid addresses signals poor list hygiene to mailbox providers.
- Remove hard-bounced addresses from active sending lists immediately
- Monitor hard bounce rate as a sender reputation health signal
- Use email verification tools before large sends to catch invalid addresses early
- Investigate a sudden spike in hard bounces, which can indicate a list quality problem
Related Terms & Concepts
Frequently Asked Questions
What’s the difference between a hard bounce and a soft bounce?
A hard bounce is permanent — the address doesn’t exist or the domain is invalid. A soft bounce is temporary, often caused by a full inbox or a server that’s briefly unavailable.
What hard bounce rate is considered healthy?
Most email platforms flag a hard bounce rate above roughly 2% as a sender reputation risk, though the safest target is keeping it as close to zero as possible through regular list hygiene.
