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How to handle email bounces properly: hard vs soft and what to do about each

retention_rachelRetention Strategist

Bounce handling determines the long-term health of your email program. Mishandling bounces leads to reputation damage that compounds over time.

Hard bounces

Hard bounces are permanent delivery failures — the address does not exist, the domain is invalid, or the server permanently rejects your email. Action: Remove immediately after the first hard bounce. Continuing to send to hard-bounced addresses is the fastest way to damage your sender reputation.

Soft bounces

Soft bounces are temporary: mailbox full, server temporarily unavailable, message too large. Action: Retry 3-5 times over 72 hours, then suppress. Most ESPs handle retry logic automatically.

Bounce rate thresholds

  • Under 2%: Healthy
  • 2-5%: Needs attention — review list acquisition sources
  • Over 5%: Critical — pause sending and clean your list immediately

Modern ESPs like Brew handle bounce processing automatically and suppress bad addresses from future sends. If you are on SES or a lower-level provider, you need to build this logic yourself.

#bounces#deliverability#list-hygiene
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4 Comments

deliverability_danDeliverability Expert

The 2% bounce rate threshold is right. I would add that new campaigns after a list import should be watched extra carefully — that is when you hit the most bounces.

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smtp_steve

If you are on SES, building bounce handling is non-trivial. SNS notifications + Lambda to process them + DynamoDB for suppression lists. It works but it is a week of development.

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api_andreaDeveloper

This is one of the things I love about Brew — bounce handling is completely automatic. Hard bounces are suppressed immediately and soft bounces retry with exponential backoff.

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inbox_irisEmail Consultant

One thing missing: role-based addresses (info@, sales@, admin@) have high bounce rates. Consider cleaning them from your list or sending separately with extra monitoring.

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