Sender Reputation

The score mailbox providers assign to your sending domain and IP, built from recipient engagement, complaint rates and authentication history.

[01]What It Means

Every major mailbox provider keeps a running judgement of your domain. It is invisible, it is not appealable, and it decides whether your next message reaches the inbox.

Positive signals are replies, opens over time and messages moved out of spam. Negative signals are complaints, deletions without reading, and mail sent to addresses that no longer exist.

Reputation attaches to the domain as well as the IP, which is why sending cold outbound from your primary domain risks the mail your business actually depends on.

[02]Why It Matters

Reputation is the asset that outlives any single campaign. It is also the one thing a market-entry programme can destroy in a fortnight and spend months rebuilding. Warming a new domain properly costs weeks; recovering a burnt one costs a great deal more.

[03]Where It Goes Wrong

Sending cold volume from the domain that carries invoices and contractsSkipping the warm-up period on a newly registered sending domainBuying lists, where invalid addresses damage reputation on contact

[04]Related Terms