Warmup SOP: New Domain to Stable
By the end of this SOP: verified SPF/DKIM/DMARC, a 4-week warmup ramp completed, and a placement test at 90%+ before any campaign volume goes live.
Before You Start
Output: 90%+ inbox placement in 4 weeks, zero shortcuts
Time required: 30-60 min for initial setup. 4 weeks of automated warmup. 20 min per week to review reports.
Sending domain separate from your primary domain. Mailbox on Google Workspace ($6/user/mo) or Microsoft 365. DNS registrar access for SPF, DKIM, DMARC TXT records. Warmup tool: Warmup Inbox, Warmbox, MailReach, Mailwarm, or a platform with built-in warmup (Smartlead, Instantly). Placement testing tool: GlockApps (2 free tests/mo) or Mail-Tester (free, 3/day).
SOP Overview
4-week ramp: volume, gates, and campaign rules
| Phase | Action | Warmup volume | Campaign sends | Gate to proceed |
|---|---|---|---|---|
| Day 0 | Domain + mailbox setup, auth records, warmup tool connected | 0 | 0 | Mail-Tester 9.0+ and all auth records pass |
| Week 1 | Warmup running, zero campaign sends | 10-20/day | 0 | No spam folder placement in warmup reports |
| Week 2 | Warmup continues, warm intros only | 20-40/day | 0 cold campaigns | Reputation score stable or improving |
| Week 3 | Warmup at mid-volume, slow campaign ramp begins | 40-60/day | 10-20/day max | Bounce rate below 1% on initial sends |
| Week 4 | Warmup at maintenance, campaign volume increases | 20-30/day maintenance | 30-80/day | Exit placement test: 90%+ inbox before full launch |
Step by Step
6 steps: Day 0 to campaign-ready domain
- Register the sending domain and provision the mailbox
Register a domain variant distinct from your primary (try-, get-, hello- prefixes or -mail suffixes). Connect to Google Workspace or Microsoft 365 and create a human-sounding mailbox: firstname@yourdomain-mail.com outperforms outreach@ or sales@ on brand-new domains.
- Configure SPF, DKIM, and DMARC before warmup starts
Add all three authentication records as TXT entries in DNS. Full steps in the SPF/DKIM/DMARC setup guide. Gate: Mail-Tester score 9.0+ out of 10 with all checks passing. Do not start warmup until this gate clears.
- Connect the mailbox to your warmup tool and set the ramp
Connect via OAuth (Gmail/Outlook) or SMTP. Set starting daily volume to 10-15 emails/day for the first 5 days. If your tool defaults higher (Warmup Inbox starts at 75/day on Basic), override it manually for week one.
- Run warmup for two full weeks with zero cold campaign sends
Warmup tools auto-open, reply to, and rescue emails from spam across their inbox network, building ISP reputation before any real recipient sees your domain. Check the dashboard weekly: a dropping score or consistent spam placement signals a config problem to fix before proceeding.
- Begin a slow campaign ramp in week 3 alongside continued warmup
Send to your highest-confidence ICP contacts first (verified addresses, not fresh exports) at 10-20/day max, with warmup at 40-60/day simultaneously. Hard bounce rate above 1%: stop that day, re-verify the list, resume at lower volume.
- Run the exit placement test and set warmup to maintenance
End of week 4: run GlockApps or Folderly Inbox Insights using your actual first campaign subject and body. Gate: 90%+ inbox placement. Below 90%: extend warmup 7-10 days, re-test. Once passed, drop warmup to 20-30/day maintenance and keep it running for as long as the domain is used for cold outreach.
Pausing warmup while campaigns run removes the positive engagement signal that offsets cold outreach volume. If you must pause warmup, pause campaign sends at the same time and restart both together.
Common Failures
What breaks in this SOP and how to fix it
Most failures trace to two causes: skipping the Day 0 authentication gate, or launching campaign sends before week 3. Both cause reputation damage that takes longer to reverse than the original warmup.
Tool Options
6 warmup tools: starting volume, monitoring, and best fit
Choose a standalone warmup tool or a sending platform with native warmup. Both execute this SOP correctly when configured to the same volume schedule.
| Tool | Best for | Starting volume cap | Monitoring included |
|---|---|---|---|
| Warmup Inbox | Solo / founders, budget-first ($15/inbox/mo) | 75 warmup msgs/day (Basic) | Spam + category placement |
| Warmbox | Solo / SMB, OAuth-first Gmail and Outlook ($15/inbox/mo) | 50 emails/day (Solo) | Spam score + DNS/blacklist audit |
| MailReach | Teams wanting warmup + automated spam tests in one tool | Up to 100/day per mailbox | Spam placement across 30+ inboxes + Slack alerts |
| Mailwarm | Teams needing live 24/7 placement tracking | 50/day (Starter, annual) | Continuous inbox vs spam tracking + optional consulting |
| Folderly | Multi-mailbox teams needing warmup + integrated monitoring | Domain/mailbox/IP level | Inbox Insights preflight + Pulse real-time alerts (free) |
| Smartlead / Instantly | Teams already on these platforms wanting all-in-one | Varies; configure manually for week 1 | Sender health monitoring; add external placement test for exit gate |
Mail-Tester checks SPF, DKIM, DMARC, SpamAssassin score, blacklists, and HTML structure in one free test. Gate: 9.0+ out of 10. Then confirm provider-level placement with GlockApps or Folderly Inbox Insights before scaling volume.
Domain is stable? Keep it that way with the placement testing SOP.
Pre-launch checks, periodic monitoring, and the corrective action sequence when placement drifts.