TL;DR
Domain reputation is the composite score Gmail, Outlook, and other mailbox providers assign to a sending domain. It blends authentication health, send volume stability, complaint rate, engagement, and spam-trap hits into one signal that decides inbox versus spam. Reps with a High Gmail rating see inbox placement above 95 percent. Low or Bad ratings cut placement below 30 percent in days.
What is domain reputation?
Every B2B rep who runs outbound is sending into a court that grades them on every message. The judge is not the prospect. The judge is the mailbox provider. Gmail and Outlook decide whether your message lands in the primary inbox, the promotions tab, or the spam folder before the prospect ever sees the subject line. That decision is driven by a single composite signal: domain reputation.
Domain reputation is not a fixed score assigned once. It is a rolling judgment based on the last seven to thirty days of sending behavior. The providers do not publish the exact formula, but the underlying signals are well understood from years of deliverability research: authentication pass rates, complaint rate, bounce rate, engagement quality, spam-trap hits, volume stability, and domain tenure.
Why domain reputation decides pipeline
Gmail handles roughly 1.8 billion active inboxes and processes more than 100 billion spam attempts per day. Outlook handles roughly 400 million inboxes. Together these two providers route the inbox decision for the majority of B2B buyers in North America and Europe. If your domain reputation drops below their thresholds, your pipeline is not slowing — it is invisible. Prospects do not see the message. They do not reject it. They never know it existed.
A team sending 1,000 emails per day at 80 percent inbox placement is reaching 800 prospects. The same team at 50 percent placement is reaching 500. That gap, applied across a quarter, is the difference between hitting quota and missing it by 30 percent. No copy hack closes that delta. Only reputation does.
How Google grades domain reputation
Google's grading system is the most transparent of any major provider. Postmaster Tools, a free dashboard any domain owner can verify, exposes four reputation tiers for both domains and IPs that send to Gmail.
| Rating | Inbox placement | Required action |
|---|---|---|
| High | 90 to 99 percent | Maintain volume discipline and engagement quality. |
| Medium | 60 to 90 percent | Audit cadence and copy. Pause new prospect imports. |
| Low | 20 to 50 percent | Cut volume by 70 percent. Mail only engaged contacts. |
| Bad | 0 to 20 percent | Full repair plan or domain switch. |
The single most important number to watch is the spam rate. Google's official threshold for compliant senders is below 0.10 percent. The hard ceiling is 0.30 percent. Crossing 0.30 even briefly causes immediate filtering of new mail. Plan on a two-week lag between the corrective action and the rating recovery.
How Microsoft grades domain reputation
Microsoft's primary diagnostic tool is the Smart Network Data Services dashboard (SNDS). SNDS reports IP status as Green, Yellow, or Red, plus a complaint rate, trap-hit count, and volume of messages filtered to junk. Green IPs deliver to the inbox at roughly the same rate as a clean sender. Red IPs are essentially blocked.
The Junk Mail Reporting Program (JMRP) is a free feedback loop that forwards user spam complaints to your abuse mailbox so you can suppress complainers immediately. Failing to enroll in JMRP is one of the most common reasons mid-stage outbound programs see their Microsoft reputation drift downward without explanation. Complaints accumulate. You never see them. The filter does.
The eight factors mailbox providers actually score
Listed in approximate order of weight:
Volume stability
Sudden volume spikes look like spam. A domain that sent 50 messages a day for six months then jumps to 500 will trigger throttling within 24 hours.
Complaint rate
The percent of recipients who mark your mail as spam. Gmail threshold is below 0.10 percent. Crossing for more than 48 hours moves you to the next tier down.
Authentication pass rates
SPF, DKIM, and DMARC must all align and pass. Misconfigured DKIM keys are the single most common technical reason for reputation problems in audits.
Engagement quality
Positive signals include replies, stars, and moving from spam to inbox. Replies are the strongest positive signal providers can measure server-side without a tracking pixel.
Bounce rate
Above 4 percent indicates poor list hygiene and triggers throttling. Above 8 percent triggers blocks. Keep bounces below 2 percent with real-time email verification.
Spam-trap hits
Spam traps are addresses that catch senders mailing scraped or stale lists. Hitting even a single pristine trap on a major blocklist can drop reputation overnight.
Content quality
URLs to blocklisted domains, deceptive subject lines, and known phishing patterns lower reputation independent of engagement.
Domain tenure
Older domains with consistent sending history earn higher baseline reputation. Plan for a 30 to 60 day warmup window on every new sending domain.
Five-step repair plan for a damaged domain
When reputation tanks, the impulse is to send harder or buy a fresh list. Every one of those moves makes the problem worse. Each step below has an exit criterion. Do not move to the next step until the prior one is clean.
Stop the bleed
Cut sending volume by 70 percent within 24 hours. Pause any new prospect imports. Remove any list segment with engagement below 5 percent. Exit criterion: daily volume down to 30 percent of prior baseline and holding stable for 48 hours.
Audit authentication
Run MXToolbox SuperTool on the sending domain. Confirm SPF, DKIM, and DMARC all pass. Fix any failure. Exit criterion: 100 percent pass rate in Postmaster for three consecutive days.
Clean the list
Verify every remaining address through NeverBounce or ZeroBounce. Suppress all addresses that did not engage in the prior 90 days. Exit criterion: bounce rate below 2 percent for one full week.
Rebuild engagement
For two weeks, send only to the engaged 20 percent. Use shorter, more personal messages. Ask one specific question that invites a reply. Exit criterion: reply rate above 8 percent and spam rate below 0.05 percent for seven consecutive days.
Ramp volume gradually
Add 20 percent more volume per week. Watch Postmaster for any reversal. Exit criterion: domain rating back at High and stable for two consecutive weeks.
When to repair vs when to switch domains
Switching domains looks like a fast win and sometimes it is. Other times it is a way to make the same mistake twice. The rule: if you can name the cause and the cause is correctable, repair. If the cause is structural — a scraped list, a deeply listed root domain, or a domain that has been Bad for three weeks of disciplined repair — switch.
When you switch, register a separate sending domain on a subdomain pattern: get-yourcompany.com or trygangly.com style domains. Keep yourcompany.com clean for transactional and one-to-one mail. A 2024 Validity report noted that subdomain segmentation alone improves overall corporate reputation by 12 to 18 percent because the high-volume cold mail no longer drags down the transactional signal.
How Gangly fits into the domain reputation workflow
Gangly is a sales workflow system that wires deliverability discipline into the same loop reps use for outreach, call prep, and CRM updates. Inside Gangly, the deliverability layer monitors Postmaster, SNDS, and blocklists for every sending domain a team has connected. When the Gmail rating slips from High to Medium, the workflow automatically pauses new prospect imports, narrows the active list to the engaged segment, and shortens the cadence to formats that drive replies.
The rep sees a single banner on the sequence dashboard explaining what changed and what to do next. No more reading deliverability documentation at 11 p.m. while pipeline silently leaks.
See it in the product
Deliverability discipline — baked into the workflow.
Gangly monitors Postmaster and SNDS for every connected domain and pauses sequences the moment reputation slips. No manual check required.
Frequently asked questions
What is a good domain reputation score in Google Postmaster Tools?
A High rating is the only score that guarantees inbox placement for cold outbound at scale. Medium means most messages land but borderline content tips toward spam. Low or Bad means the majority of messages route straight to the spam folder. For a sales domain sending more than a few hundred emails per day, treat anything below High as a deliverability incident and pause new sends until the reputation recovers.
How long does it take to repair a damaged domain reputation?
Most sales domains recover from a Medium rating in seven to fourteen days if you cut volume by 70 percent, fix authentication, and only mail engaged contacts. A Low rating usually takes three to four weeks of disciplined warmup and zero risky sends. A Bad rating, especially one tied to spam-trap hits or Spamhaus listings, can take six weeks or longer, and some domains never fully recover.
Does domain reputation transfer to subdomains?
Subdomain reputation is influenced by the root domain but tracked separately by Gmail and Outlook. A burned subdomain will not automatically burn your root corporate domain. That is why most cold outbound teams send from a separate sending domain rather than the marketing root. Keep the root clean for transactional and one-to-one sales mail.
How is domain reputation different from IP reputation?
IP reputation grades the server address that handed the message off. Domain reputation grades the from-domain in the envelope. Modern Gmail and Outlook filters weight domain reputation much more heavily than IP reputation because most senders share IPs with thousands of other tenants. The domain is the stable identifier. Shared IPs change. The domain follows the sender.
How often should I check domain reputation?
For active sales domains, check Postmaster Tools and SNDS every Monday morning. Check Spamhaus and MXToolbox after any volume spike or list import. Set alerts in your sending platform for spam rate above 0.1 percent and bounce rate above 4 percent. Treat the weekly review as a non-negotiable rep ritual.