What is the best approach for warming up an IP address for email sending?

Summary

A successful IP warmup involves a gradual increase in sending volume, starting with highly engaged recipients and using the same content you plan to send long-term. Experts and marketers recommend maintaining a consistent sending schedule, avoiding sudden volume spikes, and actively monitoring deliverability metrics using tools like Google Postmaster Tools and Microsoft SNDS. Segmentation and realistic timelines are also crucial for establishing a positive sender reputation.

Key findings

  • Engaged Recipients: Start by sending to highly engaged recipients who are likely to interact positively with your emails.
  • Gradual Volume Increase: Gradually increase sending volume to establish a stable sending reputation.
  • Consistent Sending: Maintain a consistent sending schedule and frequency (mailing more often to engaged recipients during the warmup period).
  • Monitor Deliverability: Actively monitor deliverability metrics, including bounce rates, spam complaints, and IP reputation, using tools like Google Postmaster Tools and Microsoft SNDS.
  • High-Quality Content: Use high-quality, engaging content to encourage positive interactions with your emails.

Key considerations

  • Segmentation: Segment your email list to target the most receptive subscribers during the initial warmup stages.
  • Volume Spikes: Avoid sudden volume spikes that can negatively impact your IP's reputation.
  • Realistic Timelines: Set realistic timelines for the warmup process, which can take several weeks or months.
  • Throttling: Consider throttling sends by hour, spreading sends across the day where possible, especially for non-time-sensitive emails.
  • Feedback and Interaction: The more feedback you can get during the warm up process will help reach full volume and cadence faster.

What email marketers say
12Marketer opinions

Warming up an IP address effectively involves a gradual and strategic approach. It's crucial to start with a small sending volume to highly engaged subscribers, ensuring they don't receive duplicate content. Consistent sending schedules, avoiding volume spikes, and using engaging, high-quality content are essential. Monitoring deliverability metrics and setting realistic timelines are also important for long-term success.

Key opinions

  • Gradual Volume Increase: Start with a low sending volume (e.g., a few hundred or even 50-100 emails per day) and gradually increase it daily based on engagement.
  • Engaged Subscribers First: Target highly engaged subscribers initially to build a positive sender reputation.
  • Consistent Schedule: Maintain a consistent sending schedule that reflects your typical sending patterns.
  • Avoid Volume Spikes: Prevent sudden volume increases that can trigger spam filters.
  • Quality Content: Use high-quality, engaging content to encourage positive interactions.

Key considerations

  • Content Uniqueness: Ensure subscribers do not receive the same email more than once, especially during the early stages.
  • Segmentation: Segment your list effectively to target the most receptive subscribers first.
  • Deliverability Monitoring: Closely monitor deliverability metrics like bounce rates and spam complaints.
  • Realistic Timelines: Set realistic timelines for the warmup process, which can take weeks or months.
  • Spread Sends: Spread sends across the day to avoid throttling, especially in the beginning.
Marketer view

Email marketer from Litmus shares that segmentation is vital, advising senders to initially target highly engaged subscribers and then gradually introduce less active recipients as the IP's reputation improves.

December 2024 - Litmus
Marketer view

Email marketer from Email Geeks recommends throttling sends by hour and splitting up a good base of engagers across the first few days to avoid repeating content, emphasizing that all recipients should be highly engaged.

February 2024 - Email Geeks
Marketer view

Email marketer from Email Geeks suggests ignoring specific frequency recommendations, sticking to your usual schedule, and ensuring every recipient does not receive the same email more than once.

November 2021 - Email Geeks
Marketer view

Email marketer from Email Geeks recommends sending during warmup as you would after warmup to set the right expectations.

February 2023 - Email Geeks
Marketer view

Email marketer from Reddit User emphasizes the need to avoid sudden volume spikes during the warmup, suggesting a gradual increase to prevent triggering spam filters and damaging IP reputation.

February 2024 - Reddit
Marketer view

Email marketer from Gmass states focus on engagement by sending to people most likely to open and click emails and advises that it is better to send smaller amounts of emails to highly engaged list

April 2024 - Gmass
Marketer view

Email marketer from Quora User emphasizes setting realistic timelines for IP warmup, noting that it can take several weeks to months to fully establish a positive reputation, especially for larger sending volumes.

May 2024 - Quora
Marketer view

Email marketer from Email Geeks advises spreading sends across the day where possible, especially for non-time-sensitive emails, to avoid throttling and prioritizing the best recipients in the initial hours.

June 2021 - Email Geeks
Marketer view

Email marketer from StackOverflow User advises starting with a very small number of emails per day (e.g., 50-100) and gradually increasing based on positive engagement signals.

May 2024 - StackOverflow
Marketer view

Email marketer from Digital Marketer shares that to warm up your IP focus on your known-good segments because you know they are going to be receptive to your message.

October 2021 - Digital Marketer
Marketer view

Email marketer from Email on Acid recommends using high-quality, engaging content during IP warmup to encourage positive interactions and signals to ISPs that the mail is valuable and not spam.

March 2024 - Email on Acid
Marketer view

Email marketer from Mailjet shares that consistent sending volume is key, suggesting starting small (e.g., a few hundred emails) and gradually increasing daily while closely monitoring deliverability metrics like bounce rates and spam complaints.

February 2025 - Mailjet

What the experts say
5Expert opinions

The best approach to warming up an IP address involves a gradual introduction to email filters by sending to engaged recipients, using content you intend to send long-term. Experts recommend starting with a small volume and incrementally increasing it, while closely monitoring for any issues. Sending more frequently, but only to engaged users, during warmup can speed up the process and improve deliverability.

Key opinions

  • Engaged Recipients: The initial recipients should have a history of positive engagement to signal value to mailbox providers.
  • Gradual Increase: Slowly increase sending volume, starting small (e.g., under 5000 emails/day) and increasing by 10-20% daily in the first week.
  • Long-Term Content: Use the same type of content you plan to send long-term to establish consistent filtering.
  • Increased Frequency: Mail more frequently than normal during the warm-up phase, but only to engaged recipients.

Key considerations

  • Domain/IP Introduction: IP warmup is about introducing your sending domain and IP to email filters.
  • Monitoring: Closely monitor for any issues and adjust your approach accordingly.
  • Positive Interaction: Focus on getting positive interactions to build sender reputation.
  • Yahoo TSS04: Watch Yahoo specifically - TSS04 is a sign you’re warming up too fast.
Expert view

Expert from Spam Resource explains that the initial recipients during IP warmup should be those with a history of positive engagement, as this sends positive signals to mailbox providers.

March 2025 - Spam Resource
Expert view

Expert from Email Geeks recommends using the content you’re going to send long term for warming up, ensuring the first sends are to positively engaged and non-complaining recipients.

August 2024 - Email Geeks
Expert view

Expert from Email Geeks suggests starting small (under 5000 emails a day) and increasing by 10-20% daily for the first week or so, monitoring closely, and doubling after 2-3 weeks, while watching Yahoo's TSS04 as a sign of warming up too fast.

July 2021 - Email Geeks
Expert view

Expert from Word to the Wise states that during the IP warmup process, senders should mail more frequently than normal, but only to engaged recipients. This ensures that you're getting feedback and interaction during the process and also helps you reach full volume and cadence faster.

November 2022 - Word to the Wise
Expert view

Expert from Email Geeks explains that IP warmup involves introducing your sending domain/IP to email filters by gradually increasing volume from your current setup, focusing on engaged users who will interact positively.

November 2023 - Email Geeks

What the documentation says
5Technical articles

The best approach for warming up an IP address, according to documentation from various sources, involves gradually increasing sending volume while focusing on engaged users to build a positive sender reputation. Monitoring IP reputation and deliverability through tools like Google Postmaster Tools and Microsoft SNDS is crucial for identifying and resolving issues.

Key findings

  • Gradual Volume Increase: Gradually increase sending volume to establish a stable reputation with ISPs.
  • Engaged Users First: Start by sending to your most engaged users to signal trustworthiness.
  • Monitor IP Reputation: Regularly monitor IP reputation using tools like Google Postmaster Tools and Microsoft SNDS.
  • Deliverability Insights: Use available tools to gain insights into deliverability issues, spam filtering, and feedback loops.

Key considerations

  • Reputation Building: Warming up builds a positive sender reputation with ISPs.
  • Tool Utilization: Utilize tools like Google Postmaster Tools, Microsoft SNDS, etc., to actively monitor the process.
  • Normal Schedule: Follow your normal email schedule.
Technical article

Documentation from SparkPost explains that a good IP warmup strategy involves gradually increasing sending volume, starting with your most engaged users, to build a positive sender reputation with ISPs.

December 2021 - SparkPost
Technical article

Documentation from AWS explains that AWS also recommends starting with your most engaged users, keep volumes low, and follow your normal email schedule.

March 2024 - AWS
Technical article

Documentation from SendGrid explains the importance of monitoring IP reputation through tools like Google Postmaster Tools, as this provides insights into deliverability issues and spam filtering.

April 2022 - SendGrid
Technical article

Documentation from Google explains that Google Postmaster Tools can be used to analyze delivery data, including spam rates, IP reputation, and feedback loop information, which helps identify and resolve deliverability issues during IP warmup.

June 2022 - Google
Technical article

Documentation from Microsoft explains that Microsoft's Smart Network Data Services (SNDS) provides data on IP health and complaint rates specific to Microsoft email services like Outlook and Hotmail, which is crucial for monitoring deliverability during warmup.

August 2022 - Microsoft