Sending & delivery events
Hard bounce
A permanent delivery failure — the address or domain doesn’t exist. Hard bounces should be suppressed immediately and never retried.
What causes a hard bounce
- The mailbox doesn’t exist, often a typo or an employee who has left a company.
- The domain doesn’t exist or has no mail servers.
- The receiving server permanently refuses mail from you.
Why you must never retry
Retrying a hard bounce can’t succeed, and repeatedly mailing dead addresses is one of the clearest signals of poor list hygiene. A high hard-bounce rate damages your reputation quickly, and old dead addresses can eventually become recycled spam traps.
Hard bounces in MailCraft
When an email hard-bounces, MailCraft adds the address to your suppression list automatically and fires an email.bounced webhook. Every future send to that address, transactional or marketing, is skipped until you remove it yourself.
Let MailCraft handle the details
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Full glossarySending & delivery events
Soft bounce
A temporary delivery failure — a full mailbox or a momentarily unreachable server. Soft bounces are worth retrying a few times before giving up.
Sending & delivery events
Suppression list
A list of addresses your platform will never send to again — populated automatically by hard bounces, complaints and unsubscribes to protect your sender reputation.
Sending & delivery events
Webhook
An HTTP callback your application receives in real time when an event happens — a delivery, open, click, bounce or complaint — instead of polling for status.