Deliverability
Email Warmup
Gradually increasing email sending volume on a new IP or domain to build sender reputation.
Definition
Email warmup is the gradual process of increasing sending volume on a new IP address or domain to establish positive sender reputation with mailbox providers. Instead of immediately sending large volumes (which appears suspicious), warmup involves starting with small quantities to engaged recipients and slowly scaling up over weeks. This builds trust with ISPs and improves long-term deliverability.
Pro Tip
During warmup, send only to your most engaged subscribers. Their positive engagement signals help build reputation faster.