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Deliverability

IP Warming

The process of gradually increasing email volume on a new IP address to build sender reputation.

Definition

IP warming (also called IP warm-up) is the practice of gradually ramping up email sending volume on a new or dormant IP address over weeks. This allows ISPs to observe your sending patterns and build trust in your IP. Sending high volumes immediately from a new IP often triggers spam filtering because the IP has no reputation.

Why It Matters

A new IP address has no sending history, which ISPs interpret as risky. Warming establishes a positive reputation gradually. Without warming, large campaigns from new IPs often land in spam. Proper warming is essential when switching ESPs or adding dedicated IPs.

How It Works

Start with small volumes (hundreds of emails) to your most engaged subscribers. Gradually increase volume over 2-6 weeks while monitoring bounce rates, complaints, and delivery metrics. ISPs observe consistent, positive engagement and begin trusting the IP.

Best Practices

  • 1Start with your most engaged subscribers during warming
  • 2Increase volume gradually, typically doubling every few days
  • 3Monitor deliverability metrics closely during the warm-up period
  • 4Maintain consistent sending patterns and good engagement

Managed IP Reputation

Sequenzy handles IP warming and reputation management, so you can focus on your campaigns.

Learn More

Frequently Asked Questions

Typically 2-6 weeks depending on your target volume and engagement. Higher volumes require longer warming periods. Some ESPs provide warming schedules based on your sending goals.

Usually not. Shared IPs already have established reputation from other senders. However, you still benefit from starting slowly and sending to engaged subscribers first when using any new sending platform.