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 tem…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 a…
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