Email Warm-up
Gradually ramping a new mailbox's sending and generating positive engagement so providers build trust before it sends real cold volume.
Email warm-up is the process of slowly increasing a fresh mailbox's daily send volume over several weeks while generating opens, replies, and inbox placement signals — often through automated warm-up networks that exchange friendly mail. The goal is to teach mailbox providers that the address is a normal, trusted sender before any cold campaign begins.
Warm-up is specific to the mailbox and complements domain-level setup; a new sending domain needs both the domain authenticated and each of its inboxes warmed. Skipping or rushing it is among the fastest ways to land a new inbox in spam, which is why warm-up runs continuously in the background even after a mailbox is in active rotation.
Related terms