Email warm-up

Also called: Domain warm-up, Inbox warm-up, Warming up a domain.

A brand-new domain has no sending history, so providers treat a sudden burst of mail from it with suspicion. Warm-up means starting with a small daily volume and raising it over weeks, while keeping bounces and complaints near zero.

Many cold email tools include automated warm-up networks that exchange messages between participating inboxes. These can help a new mailbox build history, but they don't fix the things providers measure most: whether real recipients complain, and whether your list bounces. Google's guidance when mail starts being deferred or bouncing is to reduce volume until the error rate falls.

Warm-up only works on a sound setup. Authenticate the domain with SPF, DKIM and DMARC first, set up a real reply path, and make the first real campaigns go to your best, verified addresses.

For local business outreach, a practical approach is to start each new mailbox with a few dozen sends a day to verified addresses in a single trade, read every reply, and only add catch-all segments once the mailbox has a clean record.

Example

An agency sets up three mailboxes on a new domain, authenticates it, and runs warm-up for two weeks. Its first campaign sends 30 emails per mailbox per day to verified roofing contractors, rising slowly as replies come in.