What send throttle is recommended for warming up an IP address with no recent sending history?

Summary

Warming up an IP address with no recent sending history requires a gradual, consistent, and engagement-focused approach. Experts and documentation emphasize the importance of progressively increasing sending volume over a period of 2-3 weeks, starting with a small, highly engaged segment of subscribers. Consistent sending patterns are crucial, and large fluctuations should be avoided. The goal is to establish that the mail is wanted and build a positive reputation with ISPs. Monitoring deliverability metrics, such as opens, clicks, and bounce rates, and utilizing tools like Google Postmaster Tools and Microsoft SNDS is essential to adjust the warm-up strategy based on ISP feedback. Pre-emptive communication with mailbox providers, like Microsoft, may also be beneficial. Since the IP has no recent history, the process should be treated as a fresh start.

Key findings

  • Gradual Volume Increase: Progressively increasing sending volume over several days or weeks is crucial.
  • Engagement Focus: Starting with highly engaged subscribers sends positive signals to ISPs.
  • Consistent Sending: Maintaining a consistent and predictable sending pattern is essential.
  • Monitor Deliverability: Closely monitoring deliverability metrics and IP reputation is vital for success.
  • No History Assumption: Treat the IP as having no prior sending history and start from scratch.

Key considerations

  • Warm-up Duration: Plan for a 2-3 week warm-up period for optimal results.
  • Initial Sending Volume: Begin with a low initial volume, such as a few hundred or a few thousand emails per day, and increase gradually.
  • Segmentation: Segment your email list and target smaller, more engaged groups initially.
  • Reputation Monitoring Tools: Utilize tools like Google Postmaster Tools and Microsoft SNDS to monitor IP reputation.
  • Proactive Communication: Consider contacting Microsoft for pre-emptive mitigation.

What email marketers say
7Marketer opinions

When warming up an IP address with no recent sending history, a gradual and consistent approach is widely recommended. Experts advise starting with a small, highly engaged segment of subscribers and incrementally increasing the sending volume over time. Consistency in sending frequency is crucial, favoring daily increases over sporadic large sends. Monitoring engagement metrics like opens, clicks, and bounce rates is essential to adjust the warm-up strategy and avoid damaging the IP's reputation.

Key opinions

  • Gradual Increase: Gradually increasing sending volume is crucial for establishing a positive IP reputation.
  • Engaged Subscribers: Starting with highly engaged subscribers helps build a good reputation quickly.
  • Consistent Frequency: Maintaining consistent sending frequency, preferably daily, is better than sending large batches sporadically.
  • Low Initial Volume: Starting with a very low initial sending volume (e.g., a few hundred or even 50 emails per day) prevents overwhelming ISPs.
  • Segmentation: Segmenting the email list allows for sending to smaller, targeted groups, improving engagement.

Key considerations

  • Monitor Engagement: Closely monitor engagement metrics (opens, clicks) and bounce rates to adjust the warm-up process.
  • Reputation Damage: Warming up an IP too quickly can negatively impact its reputation and deliverability.
  • Scaling Plan: Develop a detailed warm-up plan that spans several weeks to ensure a smooth transition.
  • Sending Limits: Scale sending limits based on subscriber engagement, increasing volume as engagement improves.
Marketer view

Email marketer from Reddit explains that starting with your most engaged subscribers is a good strategy. They suggest segmenting your list and sending to those who are most likely to open and click, which will help build a positive reputation quickly.

July 2023 - Reddit
Marketer view

Email marketer from GlockApps shares that consistent volume increases are key when warming up an IP. They advise starting with a low volume and gradually increasing it daily or every few days, depending on the overall volume and list quality.

July 2024 - GlockApps
Marketer view

Email marketer from Mailjet recommends a gradual approach to IP warm-up, suggesting starting with your most engaged subscribers and gradually increasing the volume of emails sent over time. They also suggest segmenting your list and sending to smaller, more targeted groups first.

July 2023 - Mailjet
Marketer view

Email marketer from Customer.io explains that sending limits should be scaled gradually, with a focus on monitoring opens, clicks, and bounces. They advise planning the warm up process over several weeks. They explain that as engagement improves, sending volume should increase.

June 2024 - Customer.io
Marketer view

Email marketer from Litmus shares that sending frequency during warm-up should be consistent but not overwhelming. They recommend daily sends at increasing volumes rather than sporadic large batches. They also suggest carefully monitoring deliverability rates and adjusting based on results.

September 2023 - Litmus
Marketer view

Email marketer from Email Marketing Forum explains that warming up an IP address too quickly can damage its reputation. He recommends starting with a very small number of emails and gradually increasing that number over time, monitoring the IP’s reputation along the way. He suggests starting with 50 emails per day then increasing by 50 each day.

December 2024 - Email Marketing Forum
Marketer view

Email marketer from EmailToolTester responds that the initial sending volume should be low, perhaps a few hundred emails per day, then gradually increased. They recommend closely monitoring bounce rates and engagement to ensure good deliverability.

February 2025 - EmailToolTester

What the experts say
6Expert opinions

Warming up an IP address with no recent sending history requires a multi-faceted approach focused on establishing a positive reputation. Experts recommend a structured warm-up schedule, potentially spanning 2-3 weeks, with gradually increasing sending volumes. Consistency is key, avoiding large fluctuations in sending patterns. The goal is to establish that the mail is wanted, achieved by initially targeting highly engaged users to send positive signals to mailbox providers. Given the lack of history, the process should start from scratch. Proactive communication with mailbox providers, such as requesting pre-emptive mitigation from Microsoft, is also recommended.

Key opinions

  • Structured Warm-up Schedule: A planned schedule with gradually increasing volumes (e.g., starting at 10K and increasing daily) is advised.
  • Consistency is Critical: Maintain consistent sending patterns during warm-up to avoid reputation damage.
  • Engagement Focus: Prioritize sending to highly engaged users initially to build a positive reputation.
  • Fresh Start: Assume no prior history for the IP and begin the warm-up process from the beginning.

Key considerations

  • Pre-emptive Mitigation: Consider contacting Microsoft to request pre-emptive mitigation for the IP address.
  • Wanted Mail: The warm-up process is about demonstrating that mail from the IP is wanted by recipients.
  • Reputation Monitoring: Monitor reputation data from mailbox providers to adjust the strategy.
Expert view

Expert from Email Geeks advises contacting Microsoft through their form to request pre-emptive mitigation for the IP address.

June 2023 - Email Geeks
Expert view

Expert from Email Geeks explains that the warmup process is about establishing that mail from this new subdomain/IP combination is wanted mail.

August 2021 - Email Geeks
Expert view

Expert from Email Geeks states that if an IP hasn't sent mail for a year, it should be assumed that there is no history for that domain/IP combination, and the warm-up process needs to start from scratch.

June 2023 - Email Geeks
Expert view

Expert from Word to the Wise responds that the warm-up process should be focused on engagement, advising to send initial emails only to highly engaged users. They explain that sending to engaged users provides positive signals to mailbox providers, improving the IP's reputation and deliverability.

March 2025 - Word to the Wise
Expert view

Expert from Spamresource explains that consistent sending is important during the IP warm-up process, advising to avoid large sending volume fluctuations and maintain a predictable sending pattern. They also suggest monitoring the reputation data from major mailbox providers and adjusting the warm-up strategy based on the feedback.

May 2022 - Spamresource
Expert view

Expert from Email Geeks suggests a 2-3 week warmup for the IP, assuming a different subdomain of the active domain is used. She suggests starting with 10K on the first day, 15K the second, 20K the third, and 30K the fourth, and increasing by 10K each day or doubling after the 4th or 5th day to reach 200K quickly.

March 2021 - Email Geeks

What the documentation says
5Technical articles

Warming up an IP address with no recent sending history requires gradually increasing sending volume to establish a positive reputation with ISPs. Consistent sending is crucial, along with close monitoring of deliverability metrics and IP reputation. Various tools, such as Google Postmaster Tools and Microsoft SNDS, are recommended for monitoring and adjusting sending volumes based on ISP feedback. Starting with a small batch and progressively increasing over days or weeks is the general guideline.

Key findings

  • Gradual Increase: IP warming involves progressively increasing sending volume over time.
  • Consistent Sending: Maintaining consistent sending patterns is crucial for establishing a good reputation.
  • Reputation Monitoring: Monitoring IP reputation using tools like Google Postmaster Tools and Microsoft SNDS is essential.

Key considerations

  • Deliverability Metrics: Closely monitor deliverability metrics to identify and address any issues that arise during warm-up.
  • ISP Feedback: Adjust sending volumes based on feedback and reputation data from ISPs.
  • Automation Tools: Utilize available tools, such as those from Amazon SES, to automate and optimize the warm-up process.
Technical article

Documentation from Google Postmaster Tools explains the importance of monitoring your IP reputation using their tools. They explain that a clean IP reputation is essential for successful deliverability, and provide recommendations for maintaining it during warm-up.

January 2025 - Google
Technical article

Documentation from SparkPost explains that IP warming involves gradually increasing sending volume to establish a positive reputation with ISPs. They recommend starting with a small batch and gradually increasing volume over several days or weeks. Monitor sending reputation closely.

September 2022 - SparkPost
Technical article

Documentation from SendGrid explains that warming up an IP address involves progressively increasing sending volume. They emphasize the importance of consistent sending and monitoring deliverability metrics. They provide a detailed schedule for gradually increasing volume.

January 2024 - SendGrid
Technical article

Documentation from Amazon SES explains the importance of gradually increasing your sending limits. They explain how to monitor your reputation and adjust sending volumes based on feedback from ISPs, and provide tools to help automate this.

August 2022 - Amazon SES
Technical article

Documentation from Microsoft explains the importance of using SNDS to monitor your IP’s reputation during warm-up. They outline how monitoring metrics can help to diagnose and quickly resolve problems that could affect deliverability, also that good reputations are essential for successful delivery.

December 2022 - Microsoft