What is email warm-up? A Clear Guide

Warm-up is the gradual increase of sending volume on a new IP or domain so mailbox providers build trust and do not treat sudden volume as spam.

Why it matters

Getting email warm-up right keeps you compliant and lands more mail in the inbox. See the deliverability checklist.

How Rainmail helps

Rainmail sends from your own domain on a dedicated, isolated IP with SPF, DKIM, DMARC, reverse-DNS and managed warm-up handled for you, plus an AI watching list health and deliverability — and it welcomes senders SES, SendGrid and Mailchimp reject, from $8. Run the free checker or see plans.