Bounce Impact on Deliverability

Why do bounces hurt you so much? Because sending to a high number of "unknown users" (hard bounces) is the #1 sign of a bought or scraped list. This section explains how a high bounce rate instantly destroys your sender reputation.

12 questions in this topic

How do high bounce rates affect sender reputation? What is the safe threshold for hard bounces? How do ESPs enforce bounce thresholds? How do ISPs interpret repeated invalid addresses? What’s the relationship between bounces and blocklisting? Can bounces trigger throttling? How do suppression lists protect against deliverability loss? How do bounce spikes signal list quality issues? How long do bounce rates stay in ISP memory? How to detect fake bounces from spam filters? How can spamtrap hits masquerade as bounces? How do bounces relate to engagement filtering?

Questions about Bounce Impact on Deliverability