What is domain reputation?
Also called: sending domain reputation
Domain reputation is the trust a mailbox provider attaches to your sending domain itself, separate from the IP addresses mail comes from. Because DKIM and DMARC tie messages to a domain, providers can follow your history across IPs and platforms, so switching sending service does not reset it.
Providers have moved weight from IP to domain as authentication has spread. An IP can be changed in an afternoon; a domain carries your brand, so its history is the more reliable signal of who you are.
That is why cold email teams send from separate, similar domains rather than their main one. If a campaign goes badly, the damage lands on a domain they can retire, not the one their invoices and password resets come from.
Subdomains share some reputation with their parent, so a subdomain is partial isolation, not a clean slate.
A new domain starts with no reputation, which is not the same as a good one. It needs the same gradual warm-up as a new IP, and a verified list from the first send.
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By SimpleVerifier Team · Last reviewed 2026-10-13 · All 50 glossary terms