Every email warming tool publishes some version of a “health score.” The danger with these is that they look definitive. 92! Ready to send!Except the score is almost always derived from one narrow measurement, and the actual question — “is my domain ready to handle real outbound?” — is broader than any single number can answer.
The Inbox Reputation Score in MailStrike is composite, and we've deliberately designed the dashboard to show which inputs are healthy and which aren't, not just the rolled-up output. If you only remember one thing from this article, it's this: a 92 doesn't mean “ready” until you also see the other two checks pass.
What goes into the score
Under the hood, the score is Inbox Placement Rate (IPR) — the percentage of warming emails landing in the primary inbox rather than spam — measured across a rolling 7-day window. That number runs from 0 to 100. The dashboard pulls it directly from the persona network: every email we send, we check where it landed on the receiving side, and we count it in or out.
(emails_in_inbox / emails_sent) × 100, averaged across all your active mailboxes, rolling 7 days.That's the easy part. The hard part is that IPR alone doesn't tell you whether to start sending. A score of 95 on a 3-day-old domain with two days of warming history will not survive real outbound. So the dashboard layers two additional checks on top before the “Ready for outreach” label appears.
The three readiness criteria
1. Score ≥ 90
This is your headline number. A score of 90+ means at least 9 in 10 warming emails are landing in the primary inbox. Below 70, you're in “Needs attention” territory — something is wrong, and it's usually obvious if you look at the email content, the SPF/DKIM setup, or whether the receiving side is rejecting your sender entirely.
Between 70 and 89, you're in normal warming. Improvements come from continued activity rather than from any single intervention.
2. 21+ days warmed
Receiving servers don't evaluate reputation from a single week. They build trust over time, the same way a bank evaluates a new business: a few good months matters more than one excellent week. Twenty-one days isn't magic, but it's the threshold below which we've observed inconsistent production performance even at high IPR.
If your score is 95 but you've been warming for 6 days, the score is directionally right but the sample size is too small to bet your campaign on. Wait.
3. Domain age 30+ days
A domain registered last week looks suspicious by definition. Spam infrastructure is built on freshly-registered domains, burned in days, and rotated. Receiving servers know this — they aggressively downrank young domains regardless of their authentication or content.
The fix isn't a workaround; it's patience. We pull domain age from WHOIS at mailbox connection time. If your domain is < 30 days, no amount of warming will make it “Ready for outreach” until the clock catches up.
“Reputation isn't built like a sprint. It's a slow accumulation of trust across multiple signals — and when one signal lies, the others will tell on it.”
Per-mailbox vs. domain-level health
The score you see at the top of the dashboard is your account-wide reputation — averaged across every active mailbox on your account. Below it, each mailbox in the Mailboxes view has its own score. These can diverge: one mailbox at 95, another at 78, account-level somewhere in between.
When they diverge meaningfully (say, >15 points apart), look at the lower mailbox first. It's usually one of:
- A persona mismatch — “Thorough” on a mailbox in a fast-moving industry, or “Mobile-First” on an exec inbox. The replies don't feel right to filters.
- A different infrastructure path — one mailbox routes through a relay (SendGrid, Mailgun) with a separate reputation that's dragging the score.
- A recent ramp-up — if you added the mailbox 3 days ago, it's a new line and just hasn't accrued history yet.
What the alert banner means
The yellow banner near the top of the dashboard isn't cosmetic — it surfaces issues we'd normally bury in an email or never tell you about. The most common one is the persistent DKIM warning:
These don't block warming. They flag things that will become liabilities later, especially as you scale volume. The reason they're persistent (rather than dismissible-and-gone) is that we've watched too many teams dismiss a warning, scale up six months later, and then wonder why their inbox rate cratered.
When the score drops
Reputation isn't a ratchet. It can fall. If you see a sustained drop of more than 5–8 points over a few days, the usual culprits in rough order of likelihood:
- You started real outbound at higher volume than warming, with low engagement.
- Your DKIM/SPF/DMARC setup changed (DNS edit, new provider added).
- A mailbox got temporarily blocked by its provider (Google sometimes rate-limits new OAuth-connected accounts).
- You paused warming entirely for > 7 days.
- A complaint or bounce spike — usually from a real campaign rather than warming.
The dashboard's 90-day chart will show the inflection point clearly. Hover the chart to find the day the slope changed, then look at what you did or changed that week.
The score isn't the goal
We've seen teams optimize the score itself, treating it like a leaderboard. That misses what the score is for. It's a proxy for “can my domain reliably reach inboxes I haven't emailed before?” If your score is 95 and your real campaign reply rate is 0.4%, the score did its job. If your score is 95 and your campaign reply rate is 6%, the score did its job and your copy was good. Hold both numbers in your head.