Deliverability isn't a setting you flip once — it's a system you maintain for the life of a campaign. Most teams treat it as an afterthought, then wonder why open rates collapse in week three.
Why domains get burned
Every cold email domain has a reputation score that ESPs build silently in the background. Three things wreck it fastest: sending volume that ramps too quickly, reply rates that stay flat because the copy isn't landing, and shared IP pools that get poisoned by someone else's bad sending habits.
The fix isn't "send less." It's separating your sending infrastructure from your primary domain entirely, so a deliverability hit never touches the inbox your team actually lives in.
The infrastructure stack we run
For every client, we provision dedicated sending domains that mirror the primary domain (think tryacme.com next to acme.com), each with its own SPF, DKIM, and DMARC records configured from day one — not bolted on after problems start.
- A 3-to-4-week warm-up sequence per domain, ramping volume gradually
- Daily send caps tied to mailbox age, not campaign ambition
- Rotating sender identities across a small pool of warmed inboxes
- Weekly spam-placement testing against major providers
What "healthy" actually looks like
A domain in good standing should see bounce rates under 2%, spam complaints under 0.1%, and a reply rate that's trending up, not flat. If any of those three move the wrong way, we pause sending on that domain before it's permanently damaged — the recovery cost is always higher than the pause cost.
Deliverability is a leading indicator. By the time open rates visibly drop, the damage already happened two weeks earlier.
Where most teams go wrong
The single biggest mistake is running outbound through the same domain used for customer support and billing emails. One spam complaint spike and your entire company's email reputation takes the hit — not just the campaign.
