D-10 · WARMUP · 30-DAY PLAN
Cold-start domain warmup schedule (30 days)
New domains earn trust in weeks, not hours. This 30-day ramp orders segments by engagement, caps daily volume, and defines rollback triggers.
Symptom
A rebrand launches on a fresh domain with the full list on day one: 80,000 welcomes in an afternoon. Providers defer most of it, bounces from stale addresses spike, and the domain’s first reputation record is a bulk blast to cold cohorts. Recovery takes longer than a proper warmup would have — the team pays the 30 days anyway, but as penalty rather than plan.
Partial warmups fail similarly: ramping volume while mailing oldest-first squanders early trust signals on the least engaged recipients, teaching providers the new domain means unwanted mail.
Cause
New domains lack sending history, and providers apply provisional throttling plus heightened content scrutiny. Early engagement ratios disproportionately shape the emerging reputation — opens, replies, and “not spam” rescues from engaged recipients build trust, while complaints and traps from cold cohorts cement distrust. Volume without engagement reads as snowshoe behavior regardless of legitimacy.
Authentication gaps amplify cold-start pain: missing or misaligned SPF/DKIM/DMARC on the new domain removes the only cryptographic trust signal available before history exists.
Fix
Week 1: transactional only, plus bulk to the most engaged 5–10% (opened in last 30 days). Cap daily volume near 5,000–10,000 depending on list size, one stream, frozen templates. Week 2: expand to 90-day engaged at roughly double daily caps while deferral rates stay under 3%. Week 3: add 6-month engaged, introduce the second stream on its own subdomain, and begin re-permission asks to older cohorts — never bulk to them yet. Week 4: full engaged base plus confirmed re-permissions, approaching target daily volume with per-provider pacing.
Rollback rule: any day with deferrals above 5% or complaints above 0.2% freezes expansion for 48 hours at the last stable volume. Authentication must be fully aligned before day one, with DMARC at monitoring and reports reviewed every 48 hours.
Prevention
Never let new domains inherit old lists unfiltered — validate, sunset, and re-permission first. Keep evergreen warmup segments (recent engagers) addressable for future domain or IP additions, and document the schedule as a reusable runbook with provider-specific caps. After day 30, maintain steady minimum volume; a warmed domain left idle for months cools off and re-enters provisional scrutiny.
Worked example
A rebrand moves from old-domain to new-domain with 80,000 addresses. Instead of a day-one blast, the team mails 5,000 recent openers daily in week one, expands to 90-day engaged in week two at doubled caps, introduces the marketing subdomain in week three, and re-permissions older cohorts with standalone opt-in asks. One deferral spike at day 12 freezes expansion for 48 hours, then the ramp resumes.
By day 30 the new domain carries full engaged volume at High reputation with zero block events, while the old domain forwards residual traffic during DNS transition. Total calendar time equals what a failed blast-plus-recovery would have consumed — except the list, reputation, and team morale all survive. The runbook becomes the company template for every future domain addition.