Does IP warmup work?

Yes, IP warmup is highly effective when done right. IP warmup involves gradually increasing email volume over a new or inactive IP address, allowing it to build a reputation with email service providers (ESPs) as a reliable sender. 

This process helps ensure that emails land in recipients’ inboxes rather than spam folders by demonstrating consistent, responsible sending practices.

Why IP warmup is effective:

1. Improves sender reputation: ESPs evaluate sending patterns to distinguish trusted senders from spammers. Sending too many emails right away from a fresh IP can trigger spam filters. IP warmup lets ESPs observe steady, consistent growth, which builds trust in your IP and improves inbox placement​.
2. Avoids blocklisting: Without IP warmup, new or cold IP addresses face a higher risk of being blocklisted. By warming up, you minimize the risk of hitting spam filters, giving your domain a clean reputation that sustains high email deliverability​.
3. Monitors and enhances engagement: During warmup, you can closely monitor engagement metrics—like open and click-through rates. This feedback allows you to adjust content or pacing as needed, which can improve deliverability and help build a stronger sender reputation over time.

For a typical IP warmup schedule, start by sending e.g., 100-200 emails per day to your most engaged users and increase the number gradually. If engagement rates remain high and complaints low, you can continue increasing volume.