What is email warm-up?

Email warmup is the deliberate process of establishing sender reputation before conducting real campaigns. New domains and IPs have no history, and mailbox providers treat unknown senders with suspicion.

What warmup accomplishes:

Builds sending history that filters can evaluate

Generates positive engagement signals (opens, replies)

Establishes baseline sending patterns

Demonstrates that recipients want your email

How warmup works:

Start with very small daily volumes (10 to 20 emails)

Send to recipients who will engage positively

Gradually increase volume over weeks

Monitor for deliverability problems and adjust

Why warmup matters for cold email:

Cold campaigns inherently have lower engagement than permission-based email

Without established reputation, low engagement immediately damages standing

Warmup creates a buffer of positive signals before challenging campaigns begin

Skipping warmup means starting from negative territory rather than neutral

A ship must prove seaworthiness before undertaking a challenging voyage.