Why Warmup Is Non-Negotiable
A new sending domain has zero reputation. Gmail and Microsoft don't trust it yet. Send high volume too soon and you trigger spam filters, blacklist you, or suspend the mailbox entirely.
Warmup is the process of gradually building reputation by sending small, gradually-increasing volume — most of it warmup traffic to auto-responding mailboxes — before you send any real cold outreach.
Done right, warmup takes 2–4 weeks and gets you to 95%+ inbox placement. Skipped, you spend months fighting deliverability issues that compound faster than you can fix them.
This template gives you the exact daily schedule. Follow it.
Week 0: Pre-Warmup Setup
Before you send a single email.
- Domain purchased and DNS configured (MX, SPF, DKIM, DMARC, PTR).
- Mailboxes created with real-looking names (
john.smith@, notsales1@). - Each mailbox has a display name, profile photo, and basic metadata filled in.
- Mail client shows the mailbox as set up (no empty inbox, no warning banners).
- DMARC set to
p=nonefor monitoring, NOTp=quarantineorp=rejectyet. - Warmup tool connected or platform's built-in warmup enabled.
- Seed test addresses ready (mail-tester.com, Glock Apps accounts).
Domain aging. If possible, let the domain sit for 2–4 weeks before starting warmup. New domains registered less than 30 days ago trigger additional spam filters.
Week 1: Foundation — 5 to 10 Sends/Day
Daily volume per mailbox: 5 emails.
- 100% warmup traffic (warmup tool to warmup tool).
- Zero real outreach.
Schedule. Send at varied times — no consistent burst patterns. The warmup tool handles timing automatically.
What to monitor.
- All warmup emails should arrive at the inbox (not spam). If any land in spam, something is wrong with authentication or content — fix before proceeding.
- Authentication pass rate should be 100% in Google Postmaster Tools and Microsoft SNDS.
- No bounces. Any bounce from warmup traffic indicates a misconfiguration.
Day 7 checkpoint. Run a mail-tester.com seed test. Score should be 9.0+. If lower, pause and fix the content or authentication issue before continuing.
Week 2: Foundation+ — 10 to 20 Sends/Day
Daily volume per mailbox: 10 emails.
- 80% warmup traffic, 20% real outreach.
- Real outreach limited to your best prospects — highly-targeted, manual-quality messaging.
Content rules for real sends.
- Plain text, no images, no attachments.
- 0–1 links maximum (preferably 0).
- Under 100 words.
- Personalized opening that references the prospect specifically.
- Unsubscribe link included (required by CAN-SPAM).
What to monitor.
- Bounce rate under 2%. Above that = list quality problem, stop real sends.
- Reply rate. Real outreach should get normal reply rates (2–5%). If you're getting 0% replies with 100% opens, your signature or authentication looks off.
- Seed test weekly. Score should stay 9.0+.
Day 14 checkpoint. Run full authentication audit. SPF, DKIM, DMARC all passing. Check Google Postmaster Tools — domain reputation should be "Medium" or "High".
Week 3: Ramp — 20 to 30 Sends/Day
Daily volume per mailbox: 20 emails.
- 60% warmup traffic, 40% real outreach.
- You can start diversifying recipient domains — Gmail, corporate, mixed.
Volume math. 1 mailbox × 20 sends/day = 600 sends/month. 10 mailboxes = 6,000 sends/month. 100 mailboxes = 60,000 sends/month.
What to monitor.
- Complaint rate under 0.1%. If higher, your targeting or content is triggering complaints — pause and audit.
- Microsoft SNDS status should be Green (or at minimum Yellow).
- Track inbox vs spam placement via seed tests twice a week.
DMARC ramp. If you've been on p=none, move to p=quarantine; pct=10 this week.
Day 21 checkpoint. Full deliverability audit. Reply rates should be stable. Bounce rates under 2%. Authentication all passing.
Week 4: Production — 30+ Sends/Day
Daily volume per mailbox: 30 emails.
- 40% warmup traffic, 60% real outreach.
- Full recipient domain diversity. Can run multi-step sequences.
Maximum steady-state. 30 sends/day per mailbox is the maximum for stable deliverability. Higher volume per mailbox triggers provider-specific throttling and flagging.
What to monitor.
- Inbox placement rate at 95%+ across providers (check with seed tests).
- Google Postmaster Tools domain reputation at High.
- Microsoft SNDS at Green.
- Blacklist status clean.
DMARC progression. Move to p=quarantine; pct=50 early in the week, then p=quarantine; pct=100 by end of week. Move to p=reject; pct=100 after 2 weeks of clean p=quarantine enforcement.
Day 28 checkpoint. The domain is now warm. It can sustain 30 sends/mailbox/day indefinitely as long as list quality and content remain clean.
Ongoing: Post-Warmup Maintenance
Never drop warmup to zero. Maintain 20–30% warmup traffic even after production. Warmup keeps reputation strong during low-volume periods and provides insurance against sudden reputation drops.
Monitor daily for the first month of production. Any dip in Postmaster Tools reputation, any bounce spike, any complaint rate increase — investigate immediately.
Rotate content regularly. Using the same email template for months triggers fatigue-based filtering. Rotate templates every 2 weeks.
Add new mailboxes in cohorts. Don't add one mailbox to an existing warm domain — add 5–10 at once, treat them as a new warmup cohort, run them through Weeks 1–4 while the warm mailboxes keep sending.
Scale domains, not mailboxes. Once a domain is at 100+ warm mailboxes at 30 sends/day, add a new domain rather than pushing higher per-mailbox volume. Volume per domain is the right scaling dimension.
Using This Schedule
Copy this into your project management tool. Notion, Asana, Linear, or a simple spreadsheet. Mark each daily checkpoint and monitor progress.
Do NOT accelerate. 4 weeks is the minimum for a new domain. Going faster is how you end up blacklisted. Going slower is fine if bandwidth allows.
If warmup fails at any week. Stop. Diagnose. The most common failures are (1) authentication misconfiguration, (2) content flagged as spammy, (3) list quality issues in the real-outreach portion. Fix the root cause before resuming.
If you need faster ramp. Start with aged domains (Wayback history, clean Spamhaus). Pre-configured DNS. A warmup-first tool like ColdRelay handles the whole schedule automatically.
Multi-domain campaigns. Each domain warms independently. Don't try to piggyback a new domain on an existing warm one — the reputation doesn't transfer.
Frequently Asked Questions
Can I skip warmup if I'm using an aged domain?
You can compress the schedule, but not skip it. Aged domains have some general reputation, but the mailbox-IP-domain combination is still new to receiving providers. Run Weeks 2–4 at minimum (2-week compressed warmup).
What if I'm seeing bounces during warmup?
Any bounces during warmup indicate a problem — either the warmup tool is misconfigured, or authentication is broken. Pause real outreach, run a full audit, and only resume when the issue is fixed. Warmup-to-warmup traffic should have zero bounces.
Why maintain 20–30% warmup traffic after production?
Reputation is lagging — receivers average sending behavior over days and weeks. Sustained warmup traffic keeps the ratio of 'engaged' sends high even during low-volume periods (weekends, holidays, campaign pauses). Without it, reputation drifts down during quiet periods and takes days to recover.
Does ColdRelay handle this schedule automatically?
Yes. ColdRelay runs the 4-week warmup progression automatically per domain and per mailbox. You can start sending real outreach as early as Day 1 because the warmup traffic continues in the background and maintains reputation while your volume ramps.