Domain Reputation
Domain reputation is the trust score mailbox providers assign to the domain in your From: address, based on its sending history: authentication, spam complaints, bounces, engagement, and blacklist status. Unlike IP reputation, it follows your brand wherever you send from, which is why providers like Gmail now weigh it more heavily than the IP.
- Tied to your sending domain, so it travels with you across IPs and providers
- Now weighted more heavily than IP reputation by Gmail and others
- Built from authentication, complaints, bounces, and engagement over time
- A spoofing attack or a single bad blast can damage it for weeks
What domain reputation is
Every time you send, mailbox providers record how that mail behaves and attach the verdict to the domain your recipients see in the From: address (and to the domain that signs your DKIM). Over thousands of messages this builds into a domain reputation: a running judgement of whether mail from your domain is wanted.
The crucial property is portability. An IP reputation belongs to a numeric address; rent a new IP and you start from zero. Domain reputation belongs to your brand. It rides along no matter which IP, ESP, or server you send from, so you cannot escape a damaged domain reputation simply by switching infrastructure, and you cannot lose a good one by migrating providers.
Why domain reputation now outweighs IP reputation
A decade ago an IP address told a receiver almost everything: a clean IP got mail through, a dirty one did not. That model broke down. Senders move between shared pools and ESPs constantly, and spammers churn through fresh IPs, so the IP alone is a weak signal. Mailbox providers responded by shifting filtering weight onto the domain, which a legitimate sender keeps for years and a spammer cannot cheaply replace.
This shift is visible in Google Postmaster Tools. Its domain reputation dashboard rated you High, Medium, Low, or Bad and was, for years, the single most-watched gauge of Gmail standing. Google retired that dashboard in 2025 (the legacy v1 interface closed on 30 September 2025) on the basis that a single static rating no longer captures how its filters work; deliverability is now decided by many micro-signals. The underlying concept of domain reputation did not go away, only Google’s simplified readout of it.
How to build and protect it
Domain reputation is earned slowly and lost quickly, so the priorities are consistency and defence:
- Authenticate everything. Aligned SPF and DKIM plus a DMARC record at
p=rejectstop spammers from spending your reputation by spoofing your domain. - Warm a new domain. A brand-new sending domain has no history. Ramp volume over a warmup period rather than launching with a full-list blast.
- Guard the complaint rate. Mail only engaged, consenting recipients; a complaint spike is the fastest route to a downgrade.
- Separate mail streams. Many senders send marketing from a subdomain so a campaign misfire cannot drag down the transactional mail your business depends on.
- Stay consistent. Steady volume and cadence beat erratic spikes; long silences followed by a blast read as suspicious.
How domain reputation forms and feeds delivery
Domain reputation vs IP reputation
| Domain reputation | IP reputation | |
|---|---|---|
| Attached to | Your sending domain | A specific IP address |
| Portable across IPs? | Yes | No |
| Survives a provider switch? | Yes | No, IP changes |
| Weight at Gmail today | High and rising | Lower than it once was |
| Reset by new infrastructure? | No | Yes, starts from zero |