Is domain warming effective for boosting email deliverability?

Summary

Domain and IP warming is widely recognized as a crucial process for boosting email deliverability, particularly when starting with a new domain or IP address. The core principle involves gradually increasing email sending volume to establish a positive sender reputation with ISPs (Internet Service Providers). This gradual approach helps ISPs learn sending patterns, identify legitimate senders, and avoid marking emails as spam. Key strategies include sending initial emails to highly engaged recipients, segmenting lists by engagement level, personalizing content, and following a structured IP warming schedule. While domain warming services exist, some experts caution against their use due to potential detection by abuse desks and limited long-term effectiveness if email content is poor. Documentation from Google, Microsoft, SparkPost, and AWS reinforces the importance of warming for building credibility and preventing spam filtering. It is also recommended to avoid purchasing IPs that were previously used for sending email and isolating sales/outbound emails from other business communications. Experts agree that the ultimate goal is to build trust with ISPs by exhibiting legitimate sending behavior and maintaining high email quality.

Key findings

  • Positive Sender Reputation: Domain and IP warming is essential for building a positive sender reputation with ISPs.
  • Gradual Volume Increase: Gradually increasing sending volume helps ISPs learn your sending patterns and recognize you as a legitimate sender.
  • Engagement is Key: Sending initial emails to engaged recipients improves deliverability and reputation.
  • Segmentation Strategy: Segmenting email lists by engagement level allows for targeted warming and prevents reputation damage from low-engagement subscribers.
  • Limited Long-Term Effectiveness: Domain warming services do not guarantee deliverability if the email content is poor, or negative engagement occurs.
  • Avoid Purchased IPs: It is recommended to avoid purchasing IPs that were previously used for sending email.

Key considerations

  • Email Content Quality: Ensure that your email content is high quality, valuable, and relevant to the recipients to maximize engagement.
  • Sending Practices: Adopt sending practices that signal trustworthiness to ISPs, such as sending personalized content and obtaining explicit consent before sending emails.
  • IP Warming Schedule: Develop and follow a structured IP warming schedule and gradually ramp up your sending volume over time.
  • Service Risks: Be cautious when using domain warming services, as some may employ tactics that can be detected and penalized by ISPs. It's recommended to warm up a domain independently.
  • Isolate Outbound Emails: Consider isolating sales and outbound prospecting emails to a separate domain and Google Account to protect the deliverability of core business emails.

What email marketers say
13Marketer opinions

Domain warming involves gradually increasing email sending volume from a new domain or IP address to establish a positive sender reputation with ISPs and improve deliverability. This helps ISPs recognize legitimate email activity and avoid flagging messages as spam. Best practices include sending to engaged users first, segmenting lists by engagement, personalizing content, and monitoring replies. However, some experts caution against relying solely on domain warming services, citing potential risks of detection and punishment by abuse desks, as well as the limited long-term effectiveness if email content is poor or unwanted.

Key opinions

  • Reputation Building: Domain warming is crucial for building a positive sender reputation with ISPs.
  • Gradual Increase: Gradually increasing email volume helps ISPs recognize legitimate email activity.
  • Engagement: Sending to engaged users first can boost initial results and improve deliverability.
  • Segment Lists: Segmenting email lists by engagement level allows for targeted warming and prevents reputation damage from low-engagement subscribers.
  • Limited Long-Term Effect: Domain warming alone is not effective if email content is poor or unwanted.
  • Abuse Desk Detection: Some domain warming services can be easily detected by abuse desks, leading to punishment.

Key considerations

  • Content Quality: Ensure email content is valuable and engaging to maintain a positive reputation beyond the initial warming period.
  • Engagement Level: Focus on engaged subscribers to build a strong reputation and avoid negative signals.
  • Service Risks: Be cautious of domain warming services that may employ tactics that can be detected and penalized by ISPs.
  • Monitoring: Monitor email deliverability metrics closely to assess the effectiveness of domain warming efforts and make necessary adjustments.
  • Segmentation: Consider segmenting your email list and warm up 'high' and 'medium' engagement levels. DO NOT warm up 'low' engagement lists, these can ruin your sender reputation.
Marketer view

Email marketer from Stack Overflow shares that one of the best things to help deliverability is to 'warm up' your IP address by slowly increasing the amount of mail that you send each day.

October 2021 - Stack Overflow
Marketer view

Marketer from Email Geeks mentions an email hosting provider that automatically blocks mail warming seed addresses at the SMTP level.

March 2023 - Email Geeks
Marketer view

Marketer from Email Geeks suggests warming up a domain independently by sending emails to engaged, opted-in recipients to build reputation quickly.

April 2023 - Email Geeks
Marketer view

Email marketer from GlockApps Blog answers that domain warming is important because when you start sending email from a new domain or IP address, mailbox providers don't know who you are. You need to build a reputation by gradually increasing your sending volume and engagement to avoid being flagged as spam.

April 2022 - GlockApps Blog
Marketer view

Email marketer from Mailgun Blog shares that domain reputation is crucial for deliverability. Domain warming helps build a positive reputation by gradually increasing sending volume, which ISPs see as a sign of legitimate email activity.

April 2022 - Mailgun Blog
Marketer view

Email marketer from Woodpecker.co explains that domain warming includes sending test emails, personalizing content, and tracking replies. They help gradually build your domain authority.

June 2022 - Woodpecker.co
Marketer view

Email marketer from Reddit shares that warming up a domain is crucial. Start with sending small volumes to engaged users, and slowly increase the volume. This helps establish a positive reputation and improves deliverability. It's all about building trust with ISPs.

February 2023 - Reddit
Marketer view

Marketer from Email Geeks explains that messages from many domain warming vendors are easily identified by subject, allowing for accurate detection of accounts about to send unsolicited emails. Also that these services dont work in the long term and negative engagement will always win out.

August 2023 - Email Geeks
Marketer view

Email marketer from Digital Marketer shares that to warm up a cold email list, segment the list by engagement. Start by sending your first campaign to engaged subscribers only (those with “High” engagement). These are your best subscribers and can give you an immediate lift on your results. From there, you’ll want to focus on the second segment – your “Medium” engagement subscribers. And Finally, those deemed as “Low” engagement should not be emailed, these can ruin your sender reputation.

July 2022 - Digital Marketer
Marketer view

Email marketer from ActiveCampaign shares that warming your domain or IP address helps build a sender reputation with ISPs. By sending emails slowly over time, you prove you’re a legitimate sender and can improve your email deliverability rate.

October 2022 - ActiveCampaign
Marketer view

Marketer from Email Geeks shares that if an abuse desk discovers the use of domain warming services, punishment is very likely.

June 2024 - Email Geeks
Marketer view

Email marketer from Mailjet explains email warmup is the process of building a good reputation with Internet Service Providers (ISPs) by gradually increasing the volume of emails you send from a new IP address.

June 2021 - Mailjet
Marketer view

Email marketer from SendGrid Blog explains that IP warming is a critical process that involves gradually increasing the volume of emails sent from a new IP address. This helps establish a positive sender reputation with ISPs and improves deliverability rates.

August 2022 - SendGrid Blog

What the experts say
3Expert opinions

Experts offer varying perspectives on the effectiveness of domain/IP warming for boosting email deliverability. While it's generally agreed that warming is important to avoid immediate spam filtering when using new IPs, its long-term success hinges on email quality and sender practices. One expert suggests that warming might only offer short-term benefits if the sent emails are ultimately unwanted, and recommends isolating sales emails to separate accounts. Conversely, another highlights IP warming as a key element for deliverability success, suggesting following an IP warming schedule. A consensus exists on avoiding purchased IPs and the need to warm up an IP to avoid spam filters due to sending a large volume on a new IP.

Key opinions

  • Short-Term Benefit: Domain/IP warming provides a short-term benefit by avoiding immediate spam filtering with new IPs.
  • Email Quality Matters: Long-term deliverability success depends on the quality and relevance of the email content.
  • IP Warming Schedule: Following a structured IP warming schedule and gradually ramping volume are important.
  • Avoid Purchased IPs: It's best practice to avoid purchasing IPs that were previously used for sending email.

Key considerations

  • Isolate Sales Emails: Consider isolating sales/outbound emails to a separate domain and Google Account to protect core business email deliverability.
  • Focus on Engagement: Beyond warming, ensure your sending practices target engaged recipients with relevant content.
  • Email Content: Focus on the quality of the email content, as warming is useless if the mail being sent is unwanted.
  • Warming Schedule: When warming, make sure to following a structured warming schedule to achieve the best results.
Expert view

Expert from Email Geeks explains that domain warming services might offer short-term benefits by warming the IP, but the positive effects are negated if the mail being sent is unwanted. She emphasizes that domain warming is not a long-term solution and is a waste of money if the mail quality is poor. Further she suggests isolating sales/outbound prospecting emails to its own Google Account and domain to avoid affecting opt-in emails.

September 2021 - Email Geeks
Expert view

Expert from Spam Resource explains that warming an IP address helps avoid spam filters as sending a large volume of email with a new IP will automatically get filtered to the junk folder. They also mention not purchasing IPs that used to send email.

March 2022 - Spam Resource
Expert view

Expert from Word to the Wise shares that IP warming is a key element to success with deliverability, and gives guidance on how to set up an IP Warming schedule and ramp it up.

June 2022 - Word to the Wise

What the documentation says
4Technical articles

Technical documentation from major email providers like Google, Microsoft, SparkPost, and Amazon Web Services uniformly emphasizes the importance of domain and IP warming for improving email deliverability. They highlight that gradually increasing sending volume from a new domain or IP address helps establish a sending history and build credibility with ISPs. This process allows these systems to learn sending patterns, identify legitimate senders, and avoid being flagged as spam. The general consensus is to start with a small number of messages and gradually increase the volume over time. Additionally, AWS notes that consistently sending the same volume can be a negative signal to ISPs.

Key findings

  • Establish Sending History: Domain/IP warming helps establish a sending history, making you appear legitimate to ISPs.
  • Gradual Increase: Gradually increasing email volume is crucial for building credibility and avoiding spam filters.
  • ISPs Learning Patterns: Warming allows ISPs like Google and Microsoft to learn your sending patterns and trust your emails.
  • New IP Requirement: Warming is essential when starting to send email from a new dedicated IP address.

Key considerations

  • Ramp-Up Strategy: Develop a strategic ramp-up plan for gradually increasing sending volume over time.
  • Consistent Volume: Avoid consistently sending the same volume to avoid appearing like a bot. Implement slight variations.
  • IP Type: Recognize warming is very important when sending from a new dedicated IP. It also applies to new domains.
Technical article

Documentation from Microsoft Docs answers that domain and IP warming can help establish credibility with Outlook.com. Gradually increasing sending volume allows Microsoft's systems to learn about your sending patterns and trust your emails.

February 2023 - Microsoft Docs
Technical article

Documentation from Google Postmaster Tools shares that establishing a sending history by gradually increasing email volume can improve deliverability. This helps Google learn about your sending patterns and identify you as a legitimate sender.

December 2022 - Google Postmaster Tools
Technical article

Documentation from Amazon Web Services shares that you should gradually ramp up your sending volume. As a general rule, if you're starting to send email from a new IP address, you should start by sending a small number of messages, and then slowly increase the amount you send. Also, consistently sending the same volume of messages can make you look like a bot to ISPs.

May 2022 - Amazon Web Services
Technical article

Documentation from SparkPost shares that after purchasing a new dedicated IP, you must "warm" the IP address. Warming an IP address is the process of gradually increasing the volume of email that you send through that IP address over a period of time until you reach your desired sending volume.

December 2021 - SparkPost