What is IP warm-up?

IP warm-up is the deliberate process of ramping sending volume on a fresh email-sending IP address from zero to full production volume over several weeks. The goal is to build IP-level reputation gradually so receiving ISPs come to trust the IP as a legitimate sender rather than a throwaway used for a single spam blast.

The shape of a typical warm-up curve:

• Week 1: 50 to 100 messages/day to your most engaged subscribers.
• Week 2: 200 to 500/day.
• Week 3: 1,000 to 2,500/day.
• Week 4: 5,000 to 10,000/day.
• Week 5: 20,000 to 50,000/day.
• Week 6+: normal production volume.

Required when you provision a new dedicated IP, switch ESPs, or reactivate a dormant IP. Not required when you use a shared ESP IP that is already warmed by other senders on the same pool.

See how to warm up a new IP for the full playbook.