A hard bounce is a permanent failure to deliver an email, usually because the address does not exist. A soft bounce is a temporary failure, such as a full mailbox or a server that is briefly unavailable. HubSpot stops sending marketing email to addresses that hard bounce.
When a marketing email cannot be delivered, the receiving server returns a reason. Permanent reasons, such as an unknown user or a domain that does not exist, count as hard bounces. Temporary reasons, such as a full inbox or a message that is too large, count as soft bounces. HubSpot records both on the contact and in email performance reports.
HubSpot treats hard bounces strictly. After a hard bounce, the contact is excluded from future marketing emails to protect your sending reputation. Soft bounces are retried, but an address that keeps soft bouncing can also end up excluded. The exact rules are set by HubSpot and can change, so check the contact’s email status rather than assuming.
Bounces matter because mailbox providers watch bounce rates. A list full of dead addresses signals poor list hygiene and can push your emails toward spam folders for everyone, not just the bad addresses. Bounced contacts that are still marketing contacts also cost money on plans billed by marketing contact count.
Prevent bounces at the source. Validate addresses on forms, avoid buying or scraping lists, and run re-engagement or sunset rules for contacts who have not engaged in a long time. Review bounced contacts regularly and set them to non-marketing or delete them if they serve no other purpose.
Alderbrook Events, a fictional conference organizer, imported a five-year-old attendee list and saw a 9% hard bounce rate on the first send. Open rates on later emails to its regular list also dropped. The team removed the bounced contacts, set the old list to non-marketing, and added an email validation step before any future import.
Not with marketing email by default. If you are certain the address now works, for example after the contact confirms it, HubSpot may let you clear the bounce status on the contact. Use this sparingly.
Lower is better. Many email teams aim to keep total bounce rate well under 2% per send. A sudden rise usually points to an old import or a form collecting bad addresses.
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