← Glossary
Reputation
What is Sender reputation?
A mailbox provider's running assessment of how trustworthy a sender is, based on its past mail.
How it works in practice
It's tracked separately for domains and IPs and built from bounce rates, spam complaints, spam trap hits, engagement and authentication. Each provider keeps its own view, so you can be fine at Gmail and throttled at Outlook. A good reputation is built slowly and lost quickly.
The common mistake
Treating reputation as a number you can look up. Providers don't publish one, you infer it from placement and signals.
Check it yourself
Related terms
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