How do I warm up new IP addresses for email sending?

Summary

IP warming is the process of gradually increasing email volume from a new IP to build a positive sending reputation with mailbox providers, ensuring emails reach inboxes instead of being marked as spam. This involves starting with very low sending volumes (e.g., 200 messages per IP in the first day) and gradually increasing, while avoiding doubling the volume from one day to the next. Key steps include prioritizing highly engaged recipients, using clean and segmented email lists, properly authenticating emails with SPF, DKIM, and DMARC, and consistently monitoring deliverability metrics and engagement. Separating transactional and marketing emails onto different IPs can improve deliverability. Setting clear goals, using tools like seed list testing, and following SMTP standards, along with guidelines from sender support pages, optimize the warming strategy and track progress. Consistency in sending intervals is also crucial.

Key findings

  • Gradual Volume Increase: Start with very low sending volumes and gradually increase over time to build a positive sender reputation. Avoid doubling sending volume day-to-day.
  • Engagement Focus: Prioritize sending to highly engaged recipients to generate positive engagement signals (opens, clicks).
  • List Hygiene: Maintain a clean email list by removing inactive or invalid addresses to avoid spam traps.
  • Authentication: Properly authenticate emails with SPF, DKIM, and DMARC to verify your identity to mailbox providers.
  • Monitoring: Consistently monitor deliverability metrics (bounce rates, spam complaints) to identify and address issues.

Key considerations

  • Initial Volume: Start with very low volumes, such as 200 messages per IP in the first day, and gradually increase.
  • Volume Increment Cap: Avoid doubling the sending volume from one day to the next.
  • Segmentation: Segment email lists to avoid overwhelming mailbox providers when warming up multiple IPs. Stagger the warm up process.
  • Separate IPs: Consider separating transactional and marketing emails onto different IPs to improve deliverability.
  • Consistency: Maintain consistent sending volumes and send at regular intervals to establish a predictable sending pattern.
  • Goal Setting: Establish clear goals for IP warming, such as target sending volume and engagement rates, to track progress.
  • Seed List Testing: Use seed list testing to monitor inbox placement across different mailbox providers and identify potential issues.
  • Suppression Lists: Use suppression lists to avoid sending to inactive or problematic email addresses.
  • Follow Standards: Adhere to SMTP standards and best practices for email transmission.

What email marketers say
14Marketer opinions

Warming up a new IP address for email sending involves gradually increasing the volume of emails sent to establish a positive sender reputation with mailbox providers. This process includes starting with low sending volumes, focusing on highly engaged recipients, using clean and segmented email lists, properly authenticating emails, and consistently monitoring deliverability metrics and engagement. Separating transactional and marketing emails onto different IPs can also improve deliverability. Setting clear goals and using tools like seed list testing can help optimize the warming strategy and track progress.

Key opinions

  • Gradual Volume Increase: Start with low sending volumes and gradually increase over time to build a positive sender reputation.
  • Engagement Focus: Prioritize sending to highly engaged recipients to generate positive engagement signals (opens, clicks).
  • List Hygiene: Maintain a clean email list by removing inactive or invalid addresses to avoid spam traps.
  • Authentication: Properly authenticate emails with SPF, DKIM, and DMARC to verify your identity to mailbox providers.
  • Monitoring: Consistently monitor deliverability metrics (bounce rates, spam complaints) to identify and address issues.

Key considerations

  • Initial Volume: Start with as low as 200 messages per IP the first day, only increasing in small increments.
  • Segmentation: Segment email lists to avoid overwhelming mailbox providers when warming up multiple IPs.
  • Content Quality: Focus on high-quality, engaging content to generate positive engagement signals and improve sender reputation.
  • Separate IPs: Consider separating transactional and marketing emails onto different IPs to improve deliverability.
  • Consistency: Maintain consistent sending volumes to establish a predictable sending pattern.
  • Goal Setting: Establish clear goals for IP warming, such as target sending volume and engagement rates, to track progress.
  • Seed List Testing: Use seed list testing to monitor inbox placement across different mailbox providers and identify potential issues.
  • Suppression Lists: Use suppression lists to avoid sending to inactive or problematic email addresses.
Marketer view

Email marketer from GlockApps suggests using seed list testing to monitor inbox placement during IP warming. This provides insights into deliverability performance across different mailbox providers.

January 2023 - GlockApps
Marketer view

Email marketer from Email Marketing Forum emphasizes the importance of using suppression lists during IP warming to avoid sending to inactive or problematic email addresses. This prevents negative engagement signals.

July 2023 - Email Marketing Forum
Marketer view

Email marketer from MailerLite shares segmenting your list by engagement level allows you to target your most engaged subscribers first during the IP warming process, ensuring higher open and click rates.

September 2024 - MailerLite
Marketer view

Email marketer from SendGrid suggests establishing clear goals for IP warming, such as defining target sending volume and engagement rates. This helps in tracking progress and making necessary adjustments to the warming strategy.

June 2024 - SendGrid
Marketer view

Email marketer from Email on Acid explains that focusing on high-quality, engaging content is crucial during IP warming. This helps generate positive engagement signals (opens, clicks) that improve sender reputation.

July 2021 - Email on Acid
Marketer view

Email marketer from HubSpot explains that properly authenticating your email with SPF, DKIM, and DMARC is essential for successful IP warming. Authentication verifies your identity to mailbox providers.

October 2021 - HubSpot
Marketer view

Marketer from Email Geeks recommends using the recipients / campaigns that are most likely to generate engagement (opens and clicks) because that will help get the IP warmer sooner.

April 2022 - Email Geeks
Marketer view

Email marketer from Reddit suggests when warming up multiple IPs, stagger the warmup process and segment your email lists to avoid overwhelming mailbox providers. Start with your most engaged subscribers.

March 2023 - Reddit
Marketer view

Marketer from Email Geeks explains that you shouldn't double the volume from one day to the next. Ie if it's 1000 one day on one IP, then don't send more than 2000 the next day.

September 2021 - Email Geeks
Marketer view

Email marketer from Litmus suggests closely monitoring deliverability metrics (bounce rates, spam complaints) during the IP warming process. This helps identify and address any issues that may arise.

October 2023 - Litmus
Marketer view

Marketer from Email Geeks shares it's worth separating transactional and other emails onto different IPs as that really helps mailbox providers to identify transactional and hopefully assign it a different reputation.

February 2024 - Email Geeks
Marketer view

Email marketer from Campaign Monitor explains that maintaining consistent sending volumes during IP warming helps establish a predictable sending pattern, which improves sender reputation.

January 2024 - Campaign Monitor
Marketer view

Email marketer from Mailjet shares that warming up your IP address is like introducing yourself to email providers. It’s a crucial step in building a good sender reputation and ensuring your emails reach your recipients’ inboxes.

December 2024 - Mailjet
Marketer view

Marketer from Email Geeks recommends starting IP warming off very low (200 messages per IP in the first day) and then gradually increase but never by more than 100%.

March 2022 - Email Geeks

What the experts say
5Expert opinions

Warming up an IP address involves starting with very low email volumes and gradually increasing them over time, which allows mailbox providers to learn about your sending patterns and establish a positive reputation. Consistency in sending intervals is crucial, avoiding significant fluctuations in volume. Proper email authentication using SPF, DKIM, and DMARC is essential for verifying your identity to mailbox providers. Maintaining a clean and engaged email list by removing inactive addresses helps avoid spam traps, and closely monitoring engagement metrics helps optimize your IP warming strategy and address potential issues.

Key opinions

  • Gradual Volume Increase: Start with low email volumes and gradually increase them over time.
  • Consistency: Maintain regular sending intervals and avoid significant volume fluctuations.
  • Email Authentication: Use SPF, DKIM, and DMARC records to properly authenticate your email.
  • List Hygiene: Maintain a clean and engaged email list.
  • Monitoring: Closely monitor engagement metrics (open rates, click-through rates, bounce rates).

Key considerations

  • Low Initial Volume: Begin with a very low sending volume to allow mailbox providers to learn about your sending habits.
  • Regular Intervals: Send emails at regular intervals to establish a stable reputation.
  • Verification: Ensure your email is properly authenticated to verify your identity and improve deliverability.
  • Inactive Addresses: Remove inactive or invalid email addresses to avoid spam traps.
  • Metric Analysis: Analyze engagement metrics to optimize your IP warming strategy and address any potential issues.
Expert view

Expert from Spam Resource shares that consistency is key during the IP warming process. Send emails at regular intervals and avoid large fluctuations in sending volume to maintain a stable reputation.

August 2021 - Spam Resource
Expert view

Expert from Spam Resource explains that when warming up an IP address, start with very low volumes of email and gradually increase the volume over time. This allows mailbox providers to learn about your sending habits and establish a positive reputation.

June 2024 - Spam Resource
Expert view

Expert from Spam Resource emphasizes the importance of properly authenticating your email with SPF, DKIM, and DMARC records. This helps verify your identity to mailbox providers and improve deliverability.

July 2022 - Spam Resource
Expert view

Expert from Word to the Wise responds that maintaining a clean and engaged email list is crucial during IP warming. Remove inactive or invalid email addresses to avoid sending to spam traps and damaging your reputation.

September 2021 - Word to the Wise
Expert view

Expert from Word to the Wise explains that closely monitoring engagement metrics such as open rates, click-through rates, and bounce rates is essential for optimizing your IP warming strategy. This helps identify and address any issues that may arise.

June 2023 - Word to the Wise

What the documentation says
4Technical articles

IP warming is the process of gradually increasing email volume from a new IP to build a positive sending reputation, ensuring emails reach inboxes instead of being marked as spam. Key steps include gradually increasing sending volume, authenticating email, monitoring sender reputation and deliverability rates, following SMTP standards, and adhering to guidelines from sender support pages. Consistent volume and authentication are emphasized.

Key findings

  • Gradual Volume Increase: Gradually increasing email volume establishes a positive reputation.
  • Authentication: Authenticating email is crucial for new IP addresses.
  • Monitoring: Monitoring sender reputation and deliverability rates is essential.
  • Standards Adherence: Following SMTP standards and best practices improves deliverability.

Key considerations

  • Segmentation: Segment sending volume for better deliverability.
  • Consistent Volume: Maintain consistent email volume.
  • Follow Guidelines: Adhere to guidelines from sender support pages for optimal deliverability.
Technical article

Documentation from Google details that gradually increasing sending volume, authenticating email, and monitoring sender reputation are key steps for new IP addresses. They also recommend segmenting sending volume and monitoring deliverability rates.

February 2025 - Google Workspace Admin Help
Technical article

Documentation from RFC states that following SMTP standards and best practices for email transmission is crucial, especially during IP warming. Adherence to these standards improves deliverability.

June 2024 - RFC
Technical article

Documentation from SparkPost explains that IP warming is the process of gradually increasing the volume of email sent from a new IP address to establish a positive sending reputation with mailbox providers. This helps ensure that your emails reach the inbox instead of being marked as spam.

January 2023 - SparkPost
Technical article

Documentation from Microsoft recommends monitoring their Sender Support pages and following their guidelines to ensure optimal deliverability when warming up new IPs. They emphasize consistent volume and authentication.

January 2022 - Microsoft