Soft Bounce vs Hard Bounce: The Difference and How to Handle Each

Soft Bounce vs Hard Bounce

A hard bounce is a permanent delivery failure, like a non-existent address, while a soft bounce is a temporary one, like a full mailbox, and the two demand different handling.

Hard bounces

Permanent failures: the address doesn't exist, the domain is invalid, or the server flatly rejected the mail. A hard-bounced address should be removed and never mailed again, because repeatedly hitting dead addresses is exactly what damages your reputation.

Soft bounces

Temporary failures: the mailbox is full, the server is momentarily down, or the message is too large. Soft bounces can be retried, but an address that soft-bounces repeatedly over time should eventually be treated like a hard bounce and removed.

Why the distinction matters

Handling them the same way is a mistake in both directions: retrying hard bounces burns reputation, and removing soft bounces too aggressively loses reachable contacts. Good list management branches on the two. It all feeds your overall bounce rate.

How Nitrosend handles it

Bounces are tracked per domain and hard bounces are suppressed automatically, so the permanent-versus-temporary distinction is handled rather than left to you to reconcile.

FAQ

What's the difference between a hard bounce and a soft bounce?

A hard bounce is a permanent failure like a non-existent address and should never be retried. A soft bounce is temporary like a full mailbox and can be retried a limited number of times.

Should I remove soft bounces from my list?

Not immediately, since they're temporary. But an address that soft-bounces repeatedly over time should eventually be removed like a hard bounce.