Hard Bounce
A permanent delivery failure. The address doesn't exist. Distinct from a soft bounce (temporary: full mailbox, server hiccup).
Free · no signup · last reviewed August 29, 2026
The definition
A permanent delivery failure. The address doesn't exist. Distinct from a soft bounce (temporary: full mailbox, server hiccup).
Why it matters to an owner
Hard bounces above ~2% tell inbox providers you're mailing an old or bought list. Validate before big sends; remove hard bounces instantly.
Keep going
Bounce Rate (Email)The share of sent emails that couldn't be delivered. Dead addresses (hard bounces) or temp…List HygieneThe practice of keeping an email list clean: removing bounces, validating addresses, sunse…Spam TrapAn email address that exists only to catch senders with bad list hygiene. Recycled dead ad…
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