This post is a follow-on to the Email Warmup Introduction.
It is the first in a series of articles about Email Best Practices.
Email Warm-Up Best Practices
Overview
Email warm-up is a process where you gradually increase the volume and frequency of emails sent from a new IP address or domain over time. This helps establish a positive sender reputation with Internet Service Providers (ISPs) and improves your chances of reaching the inbox instead of the spam folder. Proper email warm-up is crucial for high deliverability rates and maintaining a healthy sending reputation.
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Why Warm-Up Matters
ISPs closely monitor new IPs and domains for suspicious activity. If a high volume of emails is suddenly sent from an unknown source, ISPs may suspect spam, resulting in emails being filtered or blocked. Email warm-up helps build trust with ISPs, allowing your emails to reach your intended audience.
Step-by-Step Guide to Email Warm-Up

- Start Small
Begin with a small batch of high-quality contacts who have opted in and will likely engage with your emails (e.g., opening or clicking links). This initial
engagement signals to ISPs that your emails are valuable and wanted.
- Avoid purchased or outdated lists.
- Start with your most engaged subscribers. Segment your list to identify those who frequently open and interact with your emails.
- Relevant Content: Send content that is relevant and valuable to the recipients.
- Personalization: Personalize your emails to increase engagement rates.
- Consistency: Maintain consistent branding, tone, and content quality.
- Gradually Increase Volume
Increase the number of emails sent each day or week by a small percentage, typically around 10–20%. By gradually building up the volume, ISPs will
recognize your domain and IP as a reliable sender.
- Monitor Engagement Metrics
During the warm-up period, pay close attention to open rates, click-through rates, bounce rates, and complaint rates. High engagement and low bounce
rates are signs of a healthy email campaign, while frequent bounces or spam complaints indicate a need to adjust your approach.
- Maintain Consistent Sending Frequency
Consistency is key. Avoid sudden spikes or drops in email volume, as this can raise flags with ISPs. A steady, gradual increase helps establish trust.
- Optimize Sending Times
Make adjustments based on the performance metrics to improve engagement and reduce negative responses.
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Recommended Warm-Up Schedule (Example)
For example, if your goal is to send 10,000 emails daily:
- Week 1: Start with 500 emails per day.
- Week 2: Increase to 1,000 emails per day.
- Week 3: Send 2,500 emails per day.
- Week 4: Raise the volume to 5,000 emails per day.
- Week 5: Reach the target of 10,000 emails per day.
Common Mistakes to Avoid
- Skipping Warm-Up: Jumping straight to high volumes can lead to poor deliverability.
- Ignoring Feedback Loops: ISPs offer feedback on spam complaints, so monitor and adjust your strategy based on this feedback.
- Sending to Unengaged Contacts: Focus on engaged recipients to build your reputation.
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Conclusion
Effective email warm-up builds a positive reputation with ISPs, improves deliverability, and establishes trust with your audience. Follow these best practices, monitor performance, and maintain consistency to ensure long-term email success.