How do you warm up an email domain?

Warm each new mailbox gradually over two to three weeks before sending any real campaigns. Start at roughly 5–10 emails a day, then increase steadily — for example 10 in week one, 20 in week two, 40 in week three — building sender reputation slowly.

Use a warm-up tool that sends and receives between real inboxes, set up authentication first, and monitor domain health with tools like Google Postmaster and mail-tester.com. Begin real sending only once the mailbox is warm and the authentication checks pass.