Bounce Rate (Email)

Email bounce rate is the percentage of sent messages that fail delivery. Hard bounces indicate permanent issues, such as invalid addresses, and should be suppressed quickly. Soft bounces are temporary failures, often caused by full inboxes or server limitations, and may resolve on retry. A rising bounce rate often signals poor acquisition quality, stale data, or technical sender issues. Teams should track bounce types separately, automate suppression rules, and audit sources that generate repeated failures. Managing bounce rate is essential for sender reputation and inbox placement, because persistent delivery failures reduce trust with mailbox providers over time.