Complaint rate
The share of recipients who mark your mail as spam. Mailbox providers weigh this more heavily than bounces. Even a fraction of a percent is enough to land a domain in spam.
The share of recipients who mark your mail as spam. Mailbox providers weigh this more heavily than bounces. Even a fraction of a percent is enough to land a domain in spam.
Ready to try it on a real list?
The share of recipients who mark your mail as spam. Mailbox providers weigh this more heavily than bounces. Even a fraction of a percent is enough to land a domain in spam.
Get startedRelated
- Cold email & deliverability glossary
Plain-language definitions for the terms that come up in cold outreach and email deliverability: bounce rate, catch-all, SPF/DKIM/DMARC, sender reputation, and more.
- Bounce rate — cold email glossary
The share of sent emails a mail server refuses to deliver. A hard bounce means the mailbox does not exist; a soft bounce means it is temporarily unreachable.
- Hard bounce — cold email glossary
A permanent delivery failure: the mailbox does not exist, the domain does not accept mail, or the server has rejected the recipient for good. Hard bounces are the ones that wreck sender reputation.
- Soft bounce — cold email glossary
A temporary delivery failure: a full mailbox, a greylisting delay, or a receiving server that is down. Retrying can succeed; treating every soft bounce as a dead address thins a list for no reason.