Warming a new sending domain — a realistic 4-week schedule
Day-by-day volume targets, recipient selection, and the warning signs that mean you should slow down.
A new domain has no reputation. Send a thousand emails on day one and you'll be filtered into oblivion across most receivers. Done patiently, warm-up takes about four weeks and produces a domain you can trust for years.
Before you start
Non-negotiable prerequisites:
- SPF, DKIM, and DMARC all published and aligned.
- A clean, validated recipient list. Email-verification service before any send.
- A genuine, valuable message — receipts, account notifications, requested newsletters. Not pure marketing.
- Both Google Postmaster Tools and Microsoft SNDS configured.
Week 1 — establish baseline
- Days 1–2: 50 emails/day. Most engaged 50 recipients (recent signups, openers in the last 7 days).
- Days 3–4: 100 emails/day.
- Days 5–7: 200 emails/day.
What to watch: bounces should be near 0 (you validated the list, right?). Opens should be > 30% (your most engaged audience). Spam complaints should be 0.
Week 2 — gradual ramp
- Days 8–9: 400/day.
- Days 10–11: 800/day.
- Days 12–14: 1,500/day.
If opens drop below 20% or bounces creep above 1%, hold the previous day's volume and reassess. This is when receivers' reputation systems are starting to form an opinion.
Week 3 — broader audience
Start including less-engaged recipients but still skip anyone inactive 90+ days.
- Days 15–17: 3,000/day.
- Days 18–21: 6,000/day.
Check Postmaster Tools daily. The "domain reputation" graph should be in the medium-to-high range. If it's "low" you're sending too fast.
Week 4 — approach steady-state
- Days 22–24: 12,000/day.
- Days 25–28: target volume.
By day 28 most receivers will have a stable opinion of your domain. From here, scale further only with concurrent improvements in engagement metrics.
Warning signs to slow down
- Bounce rate above 2% on any day.
- Spam complaints above 0.1% (one in a thousand).
- Postmaster Tools showing "domain reputation: low."
- Open rate dropping by more than 25% week-over-week.
If you see any of these: cut volume in half the next day, hold for three days, then resume the schedule from where you cut.
If you only do one thing
Set up Google Postmaster Tools BEFORE you start warming. The data it gives you is the only honest signal you'll get from Gmail.
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