Summary
Domain and IP warming is a critical process involving gradually increasing email sending volume to establish a positive sender reputation with ISPs and mailbox providers. The consensus across marketers, deliverability experts, and email platform documentation emphasizes starting with the most engaged users, those who have actively opened or clicked on emails previously, and sending to a small initial group (50-100). Monitoring deliverability metrics such as bounce rates, complaint rates, and open rates is essential for informed adjustments. The process generally lasts from a few weeks to 2 months or more, depending on list size, engagement levels, and performance at each mailbox provider. Prioritizing list hygiene by cleaning and validating email addresses to prevent spam traps is crucial for a successful warmup.
Key findings
- Gradual Volume Increase: Ramp up sending volume slowly and consistently to build trust with ISPs and avoid triggering spam filters.
- Engagement-Based Targeting: Focus on sending to the most engaged users first, as positive interactions contribute to a strong sender reputation.
- Deliverability Monitoring: Closely monitor bounce rates, complaints, and open rates to identify and address deliverability issues promptly.
- Duration Variability: The warm-up period can range from a few weeks to several months, depending on factors such as list size and performance with different mailbox providers.
- List Hygiene: Maintaining a clean email list by removing invalid addresses and spam traps is crucial.
Key considerations
- List Segmentation: Segment your email list based on engagement levels to target the most responsive users during the initial warming phase.
- Mailbox Provider Differences: Be aware that different mailbox providers may have unique requirements and responses to warming efforts, necessitating tailored strategies.
- Spam Trap Avoidance: Implement robust list cleaning and validation procedures to minimize the risk of hitting spam traps, which can severely damage your sender reputation.
- Authentication Configuration: Ensure that your sending domain is properly authenticated with SPF, DKIM, and DMARC to improve deliverability.
- Content Quality: Focus on providing valuable and relevant content to increase engagement and reduce the likelihood of spam complaints.
- Testing & Monitoring Infrastructure: Monitor smtp replies during ramp up and use the initial sending phase to test out the new setup before sending to large volumes.
What email marketers say
12 marketer opinions
Domain warming is a critical process for establishing a positive sender reputation with ISPs. The strategy involves gradually increasing email volume, starting with the most engaged users, to demonstrate trustworthiness. Duration typically ranges from a few weeks to a couple of months, depending on list size, engagement levels, and performance with different mailbox providers. Monitoring metrics like bounce rates, complaints, and open rates is essential for making informed adjustments to the warming schedule.
Key opinions
- Gradual Ramp-Up: Increase sending volume slowly and steadily to establish trust with ISPs.
- Engagement Focus: Prioritize sending to the most engaged users first, as positive interactions build a strong reputation.
- Monitoring: Closely monitor deliverability metrics such as bounce rates, complaints, and open rates to identify and address any issues promptly.
- Duration Variability: The warming period can vary, from a few weeks to several months, depending on factors like list size and mailbox provider performance.
Key considerations
- List Segmentation: Segment email lists based on engagement levels to target the most responsive users during the initial warming phase.
- Mailbox Provider Differences: Be aware that different mailbox providers (e.g., Gmail, Yahoo, Microsoft) may respond differently to warming efforts, requiring tailored strategies.
- Content Quality: Focus on delivering valuable and engaging content to encourage positive interactions and avoid spam complaints.
- Infrastructure Testing: Initial sends should be used to test your sending infrastructure and ensure emails are properly authenticated (SPF, DKIM, DMARC).
- Clean Email List: Before starting the warmup process, the email list needs to be cleaned, to remove inactive and invalid emails.
- Consistent sending: Maintain a consistent sending pattern that gradually increases in volume and frequency. Avoid sudden spikes or drops in sending activity.
Marketer view
Email marketer from Neil Patel advises starting with transactional emails to build trust and then segment lists based on engagement to warm up the domain effectively. Focus on quality content and consistency.
1 May 2022 - Neil Patel
Marketer view
Email marketer from Email Marketing Forum suggests starting with essential emails only, then increase volume slowly. Use a good tracking system to evaluate results.
15 Oct 2023 - Email Marketing Forum
What the experts say
3 expert opinions
Experts emphasize that successful domain/IP warming centers on establishing a strong sender reputation with mailbox providers. This involves prioritizing engagement by initially sending to the most responsive users while cautiously increasing volume. A crucial aspect is maintaining list hygiene by cleaning and validating email addresses to avoid spam traps. The warming period typically lasts 30-60 days, with the initial weeks dedicated to testing infrastructure with smaller send volumes.
Key opinions
- List Hygiene: Cleaning and validating email lists to avoid spam traps is essential for a successful warm-up.
- Engagement First: Starting with highly engaged users helps build a positive sender reputation quickly.
- Gradual Volume Increase: Slowly increasing sending volume allows for monitoring and adjustment as needed.
- Testing Phase: Dedicate the first few weeks to testing your sending infrastructure with smaller volumes to identify potential issues.
- Duration: Expect the entire process to last between 30 and 60 days.
Key considerations
- Spam Trap Avoidance: Implement robust list cleaning and validation processes to minimize the risk of hitting spam traps.
- Infrastructure Readiness: Ensure your sending infrastructure is properly configured and tested before beginning the warm-up process.
- Monitoring and Adjustment: Continuously monitor deliverability metrics and adjust your strategy as needed based on performance and feedback from mailbox providers.
Expert view
Expert from SpamResource shares that IP warming should focus on volume and engagement. This expert mentions that it will take 30-60 days, with the first 2 weeks you should only be sending to smaller volumes to test out your infrastructure.
4 Jun 2025 - SpamResource
Expert view
Expert from SpamResource explains that one key part of warming up is to avoid spam traps by cleaning your list and validating your email addresses. It's important to start with a clean list for the best results.
23 Oct 2023 - SpamResource
What the documentation says
4 technical articles
Technical documentation from leading email platforms consistently advises a gradual increase in sending volume when warming up a domain or IP to establish a positive reputation. Avoiding sudden spikes and maintaining a consistent sending pattern is crucial to prevent triggering spam filters. Segmentation based on engagement and adherence to email authentication best practices (SPF, DKIM, DMARC) are also key components of a successful warming strategy. These platforms also tend to provide mechanisms for automatic increases to send volume as you improve your email reputation.
Key findings
- Gradual Volume Increase: A gradual ramp-up in sending volume is essential for establishing a positive sender reputation.
- Consistent Sending Patterns: Maintaining a consistent sending frequency and volume is important for building trust with ISPs.
- Engagement Segmentation: Segmenting lists based on engagement levels and sending to the most active users first is recommended.
- Authentication Practices: Proper email authentication (SPF, DKIM, DMARC) is crucial for establishing credibility and avoiding spam filters.
Key considerations
- Spike Avoidance: Avoid sudden spikes in sending volume to prevent triggering spam filters and damaging your reputation.
- Authentication Setup: Ensure that SPF, DKIM, and DMARC records are correctly configured for your domain.
- ISP Specific Guidelines: While general guidelines are helpful, be mindful of individual ISP requirements and best practices.
- Segmentation Strategy: Develop a clear segmentation strategy based on engagement to target the right users during the warming process.
Technical article
Documentation from AWS SES notes that they automatically increase your sending limits over time as you establish a good sending reputation.
28 Nov 2022 - AWS SES
Technical article
Documentation from Microsoft indicates that a consistent sending pattern with good email authentication practices is crucial for establishing a positive reputation and avoiding spam filters. Warm up gradually by increasing volume over time.
15 Jan 2024 - Microsoft
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