Domain reputation: a year in numbers
We tracked the deliverability behavior of 38 customer sending domains across 2025. Here are the numbers that actually mattered.
I keep a spreadsheet. For the last 14 months I have been tracking the deliverability behavior of 38 sending domains across our customer base. Not because we sell deliverability as a product, but because we have to understand it to keep our outbound features honest. Here is what the data actually said in 2025.
The headline numbers
- Average inbox placement at Google: 91.2 percent for domains following our hygiene playbook, 67.4 percent for domains not
- Average inbox placement at Microsoft: 78.1 percent for compliant domains, 51.3 percent for noncompliant
- Bounce rate above 3 percent in any 24 hour window was the single best leading indicator of an upcoming reputation drop, by about 9 days
- Domains that aged past their first 90 days without a major spam complaint were 4 times more likely to maintain placement above 85 percent for the rest of the year
The lesson on first 90 days
The first 90 days of a domain's life are determinative. If you can avoid a spam complaint, keep bounce rate below 2 percent, and maintain consistent reply engagement, the domain enters a stable reputation band that is genuinely hard to disturb. If you push hard early, you spend the rest of the year clawing back trust.
What we did not expect
We expected sender reputation to be a slow-moving variable. It is not. We watched domains drop two reputation tiers inside 72 hours after a single bad send. The recovery curve is genuinely much steeper than the drop curve. That asymmetry is what makes deliverability scary and what makes the hygiene playbook worth following.
A single bad campaign in week three can erase six weeks of careful warmup. The asymmetry is real. Slow down in the first quarter.
The hygiene playbook in five lines
- Warm for 21 days minimum before any external send
- Cap volume at 40 per mailbox per day in the first 90 days
- Stop sends immediately if bounce rate crosses 3 percent in a 24 hour window
- Vary content. Templates produce predictable patterns that reputation models punish
- Maintain a verified suppression list, ideally shared across every domain you own
“Reputation is not a vendor problem. It is a discipline problem. The customers who treat it as discipline outperform the ones who treat it as a setting.”
If this resonated, it'll feel familiar in the product.
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