What is Email Warmup?
The process of building sender reputation for new email accounts before launching campaigns.
Email warmup is the gradual process of increasing sending volume from a new mailbox to build trust with email providers like Gmail and Outlook. New accounts that immediately send hundreds of cold emails get flagged as spam. Warmup tools simulate real email activity — sending, receiving, opening, and replying — to establish a positive sender reputation. Most warmup periods last 2-4 weeks, after which the mailbox is ready for cold outreach. Pre-warmed mailboxes from Coldmails.ai skip this wait time entirely.