IP warming
Gradually ramping volume on a new sending IP address so ISPs can build positive reputation.
IP warming is the process of gradually ramping email volume on a new dedicated IP address. Like domain warming, the goal is to build positive reputation with mailbox providers before high-volume sends. A cold IP that suddenly attempts to send 100k emails will be aggressively filtered or outright rejected.
A standard IP warming schedule starts at 50–100 emails per day, doubles every 2–3 days, and reaches full target volume after 4–8 weeks (depending on target volume). Engagement matters during warming — sends should go to your most-engaged segments so the early signal to ISPs is positive.
Most small senders use shared IPs (provided by their ESP) where reputation is pooled across the ESP's other customers. Dedicated IPs are valuable above ~50k emails per month, where your own reputation becomes the dominant signal. Below that volume, shared IP usually outperforms a dedicated IP that doesn't get enough send volume to build a clear reputation.