Cold Email Inbox Warmup

Run this before any new domain or mailbox sends cold email. It produces a ramp schedule and a clear go/no-go decision for opening campaign volume.

The play

1. Separate the asset from the brand: cold email runs on secondary domains, never the company's primary domain. The primary's reputation is not a chip to gamble.
2. Give a fresh domain two weeks of silence after setup: authentication configured, mailboxes created, signatures and profile pictures in place, zero cold sends. Age is part of reputation.
3. Warm for at least three weeks before campaign volume: start at a handful of sends per day per mailbox, grow the daily count a little every few days, and keep replies flowing; a mailbox that only sends and never receives looks like a cannon, not a person.
4. Cap real campaign volume per mailbox at 20-30 cold sends per day, and keep warm-up activity running in the background even after campaigns start. Scale by adding mailboxes and domains, not by pushing one inbox harder.
5. Go/no-go before launch: spot-check where warm-up messages land. Anything worse than consistent inbox placement means the ramp continues; launching into the spam folder burns the list and the domain together.
6. On a placement drop or a bounce spike mid-campaign: cut volume in half, hold for several days, and only ramp back one step at a time: the same discipline as the initial warm-up, at smaller scale.

What good looks like

• Good operators treat sending volume as something a mailbox earns, week by week; the mediocre version buys a domain on Monday and blasts 200 sends on Friday, then wonders why replies stopped.
• The tell that separates experts: they watch placement and bounce rate per mailbox, not per campaign, and they act on the first bad signal instead of the fifth.
• Consistency beats speed here exactly as on social channels: identical, boring, daily behavior is what reputation systems reward.
• Done well, every mailbox reaches campaign volume with steady inbox placement, bounce rates stay low, and a placement incident costs days, not domains.

Rules

• MUST warm every new domain and mailbox before campaign volume; no exceptions for deadlines.
• MUST keep cold volume per mailbox at 20-30 sends per day; scale with more mailboxes, not more pressure.
• MUST keep warm-up activity running after campaigns start.
• NEVER send cold email from the primary company domain.
• NEVER keep sending through a placement drop; cut volume and re-ramp.