What “domain reputation” means, and who keeps it
There is no single sender reputation. Each receiving provider keeps its own score for your domain and your sending IPs, built from what it has seen: how much of your mail its users report as spam, how much goes to addresses that do not exist, how much gets opened and replied to, whether it authenticates, and how suddenly the volume changes. Google shows its verdict to verified domain owners in Postmaster Tools as a tier (Bad, Low, Medium, High) and a spam rate; Microsoft shows complaint and trap data per IP in SNDS. Neither number is visible to anyone else, and no third-party “reputation score” can see it either.
What is public is the evidence those scores draw on, and that is what this report reads. A listing on a blacklist the big providers consult, a missing DKIM key, a DMARC record that never got past monitoring, an address with no reverse DNS, a domain registered last week: each is a reason a filter needs to go no further. Clear them and you have the floor. The rest is behavior, and behavior is what warming and a placement test are for.
What the report reads
- Blacklists. The domain's IPv4 address against the IP lists our blacklist checker queries (Spamhaus ZEN and its component lists, SpamCop, Barracuda, UCEPROTECT, PSBL and the rest), and the domain name itself against Spamhaus DBL, SURBL and URIBL. A listing links straight to its removal guide. Critical and major lists set the area to “Problem”; standard lists to “Attention”.
- Authentication. SPF (one record, under 10 lookups, a real all mechanism), DKIM on the 17 common selectors with the key length, DMARC with its policy and alignment mode, and MX with the hosting provider identified.
- Infrastructure. Reverse DNS of the domain's address, forward-confirmed. This matters when the address sends mail directly; mail through Google Workspace or Microsoft 365 leaves from their addresses, which carry PTR records of their own.
- Domain age. The registration date from the registry's RDAP record, which is authoritative where WHOIS is often hidden. Under 30 days is flagged; under 90 is a caution.
31 active lists, by severity
How to read the result
The report counts the areas that are clear, out of the areas it could check, the same way the auth checker does. That number is not a reputation score and does not pretend to be one. A domain can pass every area and still land in spam at Gmail because its spam rate is high; a domain can fail an area (no DMARC, say) and land fine for a while. Read the areas as gates. A closed gate is a reason a receiver can reject or spam-file without weighing anything else, so it is what you fix first, and the fix order under the report is sorted that way: blacklists on enforced lists, then broken authentication, then missing records, then infrastructure, then age, then the providers' own consoles.
What no public checker can see
The spam rate Google shows in Postmaster Tools is the single most decisive number in email, and it is visible only to the domain's owner. SNDS is the same for Microsoft. If you send from your own IPs, Sender Score and Talos give a third-party read on those IPs. And the only way to know where a message actually lands, provider by provider, is to send it to inboxes whose folders you can read: that is what a placement test is, and MailStrike's Free Deliverability Test runs one for you. Use this report to clear the gates; use a placement test to see what the providers decided.
Questions about domain reputation
Are sender reputation scores public?
Mostly not. Google Postmaster Tools shows a domain's reputation (Bad, Low, Medium, High) and spam rate only to the domain's verified owner. Microsoft SNDS shows complaint and trap data only for IPs you register. Validity's Sender Score is per IP and sits behind a free account. Cisco Talos publishes a lookup. What is fully public is the evidence those scores are built from: blacklist listings, authentication records, reverse DNS and domain age, which is what this checker reads.
What is a good domain reputation?
At Google, a High tier in Postmaster Tools with a spam rate under 0.1%. At Microsoft, a green SNDS status with no trap hits. Publicly, a domain with no listings on the enforced blacklists, SPF, DKIM and DMARC all passing, forward-confirmed reverse DNS on any address that sends directly, and an age past the first months. None of those alone makes placement good; together they are the floor placement is built on.
Why is my domain reputation bad if I am not on any blacklist?
Because the providers score behavior, not listings. Spam complaints, mail sent to addresses that do not exist, low engagement and volume spikes all lower a domain's standing at Gmail and Microsoft without any blacklist noticing. A clean blacklist report rules out one cause; Postmaster Tools and SNDS show the rest, and a placement test shows the result.
Does a new domain have a bad reputation?
It has none, which receivers treat with suspicion because spam infrastructure is built on freshly registered domains. This checker reads the registration date from RDAP: under 30 days is flagged, under 90 days is a caution. The fix is patience plus warming, which builds the engagement history a young domain lacks.
How long does it take to repair a domain's reputation?
Delisting from a blacklist that offers self-service removal takes minutes to a day once the cause is fixed; authentication fixes take effect as soon as DNS propagates. Rebuilding the reputation the providers keep is slower: it moves on engagement over weeks, which is why MailStrike's ramp runs 21 days and why getting out of spam is measured in weeks, not days.