Hard bounce (email)
ما هو Hard bounce (email)?
هذا المصطلح متوفر حاليًا باللغة الإنجليزية فقط.
A hard bounce is a permanent email delivery failure — the receiving server rejects the message because the recipient address doesn't exist, the domain doesn't resolve, or the server refuses mail from your sender entirely — and retrying the same message will fail every time. Sending platforms classify the failure as terminal and route the address to a suppression list, so no future batch tries it again and the sender's reputation stops taking the hit. A hard bounce is the opposite of a transient soft bounce.
More detail
The permanent causes are well-known: an address that never existed (a typo, a fabricated signup), a domain whose MX record no longer resolves, or a recipient server that hard-rejects your sender on a policy block. Each one fails identically no matter how many times the platform retries, so the retry loop never resolves it — the only deliverability-safe response is to stop sending to that address and investigate the source (list hygiene at signup, or a sender-side block).
Orbit's email delivery log marks the failure as terminal and the email channel's bounce tracker increments the hard-bounce counter per address — the same signal that feeds both the suppression list (which blocks dispatches, no matter which campaign or flow tries the address next) and the sender-reputation inputs mailbox providers score.
الأسئلة الشائعة
- What makes a bounce 'hard' instead of 'soft'?
- Permanence. A hard bounce means the failure will recur identically on every retry — the address doesn't exist, the domain doesn't resolve, or the recipient server rejects your sender outright — so the only correct response is suppression. A soft bounce is a temporary failure (mailbox full, server briefly unavailable) that might succeed on a later attempt, so the platform keeps it in the retry loop until either it delivers or the validity window closes it as expired.
- Why should a hard-bounce address be suppressed immediately?
- Because every additional attempt at an undeliverable address compounds the reputation damage for zero upside — mailbox providers treat sending to known-bad addresses as a list-hygiene signal, and the sender's score dips further with each wasted attempt. A suppression list entry ends the bleed in one place, so no batch from any campaign or flow reaches that address again.
- What's the difference between a hard bounce and an expired message?
- A hard bounce is a terminal failure — the recipient server rejected the delivery permanently. An expired message exhausted its retry window as a soft bounce without ever converting to delivery; the failure is classified as transient-then-gave-up rather than immediately permanent. Both remove the address from circulation, but the distinction decides whether the platform suppresses right away (hard bounce) or only after the validity window closes (expired).
See also
Build it on Orbit
Voice, messaging, email, video, and AI agents on one platform and one pay-as-you-go bill. Start free — no credit card required.