Cold Email & Outreach
How to Warm Up a New Domain & Mailbox for Cold Outreach
Priya Sharma
Lead Deliverability & Outreach Specialist
October 10, 2026 7 min read
TL;DR / Quick Summary
Domain warmup requires an incremental 21-day ramp schedule starting at 5 emails daily, paired with peer reply exchanges to train spam filters that your mailbox engages in real conversations.
The 21-Day Sending Ramp Calendar
Days 1-5: 5 emails/day (manual correspondence with trusted partners). Days 6-10: 15 emails/day. Days 11-15: 25 emails/day. Days 16-21: 35-40 emails/day.
Frequently Asked Questions
Can I skip warmup if I buy an aged domain?
No. If an aged domain switches sending IPs or mail providers, recipient filters treat it as a fresh sender.
Written by Priya Sharma
Lead Deliverability & Outreach Specialist
Specializes in cold email inbox placement, SPF/DKIM/DMARC server infrastructure, and anti-spam deliverability algorithms.
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