Should I continue sending from my old ESP while warming up a new IP address?

Summary

The consensus among experts, email marketers, and documentation sources is that you should continue sending emails from your old ESP while warming up a new IP address. Overlapping the use of both ESPs is a best practice for maintaining a consistent sending presence, preventing a sudden drop in email volume, and preserving your sending reputation. Focus on sending to your most engaged subscribers from the new IP to establish a positive reputation with ISPs, while gradually reducing the volume of emails sent from the old IP. It is crucial to monitor deliverability metrics for both IPs and inform subscribers about the change. Delay moving revenue emails to the new IP until warm up is complete.

Key findings

  • Overlap is Key: Overlapping the use of both old and new ESPs is a recommended practice for IP warming.
  • Maintain Sending Reputation: Continuing to send from the old ESP helps maintain your overall sending reputation.
  • Engaged Subscribers First: Focus on sending to your most engaged subscribers from the new IP to build a positive reputation.
  • Gradual Transition: Slowly move subscribers from your old ESP to the new one, reducing volume on the old while increasing on the new.
  • Consistent Presence: Maintain a consistent sending presence to avoid sudden drops in email volume, which negatively impacts deliverability.

Key considerations

  • Segment Audience: Segment your audience and prioritize sending to your most engaged subscribers from the new IP.
  • Monitor Metrics: Continuously monitor deliverability metrics (open rates, bounce rates, etc.) for both IPs.
  • Communicate Changes: Inform subscribers about changes to your email sending infrastructure.
  • Delay Revenue Emails: Delay moving revenue generating emails over to the new IP until the warm up process is complete.
  • Avoid Sudden Stops: Avoid stopping sends from the old ESP entirely to prevent sudden negative impacts on deliverability.

What email marketers say
10Marketer opinions

When warming up a new IP address, it's generally recommended to continue sending emails from your old ESP. This helps maintain a consistent sending presence and avoids a sudden drop in email volume, which can negatively impact deliverability. The key is to transition gradually, overlapping the use of both ESPs. Focus on sending to your most engaged subscribers from the new IP to establish a positive sending reputation, while reducing the volume of emails sent from the old IP over time. Monitoring the performance of both IPs, including open rates and bounce rates, is crucial during this process.

Key opinions

  • Maintain Sending Reputation: Continuing to send from your old ESP helps maintain your overall sending reputation during the IP warm-up phase.
  • Gradual Transition: A gradual transition, overlapping the use of both ESPs, is crucial for a smooth migration.
  • Engagement Focus: Prioritize sending to your most engaged subscribers from the new IP to build a positive reputation with ISPs.
  • Volume Reduction: Reduce the volume of emails sent from your old IP over time as the new IP warms up.
  • Performance Monitoring: Closely monitor the performance of both IPs, including open rates and bounce rates, to ensure deliverability.

Key considerations

  • Audience Segmentation: Segment your audience and prioritize sending to your most engaged subscribers from the new IP.
  • Gradual Increase: Gradually increase the volume of emails sent from the new IP over time, while decreasing the volume from the old IP.
  • Monitor Metrics: Continuously monitor deliverability metrics (open rates, bounce rates, etc.) for both IPs and adjust your strategy accordingly.
  • Avoid Sudden Drops: Avoid stopping sends from the old ESP entirely to prevent a sudden drop in email volume.
  • Plan for Overlap: Plan for a period of overlap where you're actively sending from both your old and new ESPs.
Marketer view

Email marketer from Iterable explains that you should segment your audience during IP warm-up. They say you should start by sending to your most engaged subscribers to establish a good reputation with ISPs.

July 2023 - Iterable
Marketer view

Email marketer from Email Marketing Forum states that it is important to monitor the performance of both IPs, watching open rates and bounce rates of both sets of sends, and if things are going well, slowly ramp down the old IP as the new one increases

June 2021 - Email Marketing Forum
Marketer view

Email marketer from Email Marketing Forum suggests to continue using the old ESP, but reduce the volume of emails sent from it over time as the new IP warms up. This ensures a smooth transition and avoids deliverability issues.

June 2024 - Email Marketing Forum
Marketer view

Email marketer from SendGrid shares that you should continue sending emails from your old ESP while warming up a new IP address, to maintain your sending reputation. They suggest gradually increasing the volume of emails sent from the new IP over time, while decreasing the volume from the old IP.

February 2022 - SendGrid
Marketer view

Email marketer from Reddit suggests overlapping ESPs during migration is the best practice. They advise sending higher engagement emails from new IPs and sending less engaged emails from old IPs during the warm up phase.

December 2021 - Reddit
Marketer view

Email marketer from Campaign Monitor advises against stopping sends from the old ESP entirely. They say you should gradually reduce sending volume on the old IP while increasing on the new IP to avoid any sudden negative impact on deliverability.

June 2023 - Campaign Monitor
Marketer view

Email marketer from ActiveCampaign recommends focusing on engagement during the IP warm-up phase. They say you should send emails to your most engaged subscribers from the new IP to establish a positive sending reputation.

June 2024 - ActiveCampaign
Marketer view

Email marketer from Mailjet Blog explains that you should send emails from both your old and new IP addresses during the warm-up process. Start by sending to your most engaged subscribers from the new IP and gradually increase the volume.

February 2024 - Mailjet Blog
Marketer view

Email marketer from HubSpot shares that transitioning your email sending gradually is key. They suggest slowly moving subscribers from your old ESP to the new one, monitoring deliverability metrics closely during the process.

December 2023 - HubSpot
Marketer view

Email marketer from Email on Acid suggests that maintaining a consistent sending presence is important. Continue sending from your old ESP to avoid a sudden drop in email volume, which can negatively impact deliverability.

March 2021 - Email on Acid

What the experts say
6Expert opinions

Experts generally recommend overlapping migration periods when warming up a new IP address with a new ESP. This means continuing to send from your old ESP, focusing on less engaged subscribers or specific types of emails like revenue emails, while sending to the most engaged subscribers from the new IP. Sending a notice to subscribers about the change is also suggested. It is best not to stop sending completely from your old ESP to keep a consistent sending volume.

Key opinions

  • Overlap Migration: Overlapping sending from both old and new ESPs is a recommended best practice.
  • Segment by Engagement: Send to the most engaged subscribers from the new IP and less engaged from the old IP.
  • Delay Moving Revenue Emails: Keep revenue-generating emails on the old IPs until the warm-up process is complete.
  • Communicate the Change: Inform subscribers about the change in sending infrastructure.

Key considerations

  • Gradual Transition: Avoid abrupt changes in sending volume from either ESP.
  • Engagement-Based Segmentation: Carefully segment subscribers based on engagement levels for optimal deliverability.
  • Monitor Performance: Continuously monitor deliverability metrics to ensure a smooth transition.
  • Focus on Active Users: Focus on the most active and engaged users when sending from the new IP.
Expert view

Expert from Email Geeks suggests sending a notice saying "we are making changes to improve our services, and our [from address / other ] is changing be sure to look out for [new thing] here".

June 2024 - Email Geeks
Expert view

Expert from Email Geeks recommends starting with the most engaged subscribers on the new IPs and sending to less engaged subscribers from the old IPs, and not letting people forget you.

December 2024 - Email Geeks
Expert view

Expert from Email Geeks suggests keeping revenue emails on the old IPs until the warmup is done, then moving them over.

April 2022 - Email Geeks
Expert view

Expert from Email Geeks recommends overlapping migration whenever possible.

June 2022 - Email Geeks
Expert view

Expert from Word to the Wise explains that it is best practice to overlap sending from old and new systems when migrating ESPs and warming up new IPs. Don't stop sending completely from your old setup.

April 2021 - Word to the Wise
Expert view

Expert from Spam Resource responds that during IP Warm up you can continue sending from your old ESP in a lower volume, focusing on your most active and engaged users.

November 2023 - Spam Resource

What the documentation says
4Technical articles

Technical documentation from various sources emphasizes the importance of a gradual approach when warming up a new IP address. When transitioning to a new ESP, it's crucial to gradually increase sending volume from the new IP while phasing out the old ESP. Avoiding sudden changes in sending volume is key to maintaining a consistent sending reputation and preventing deliverability issues. Starting with small volumes enables you to monitor deliverability and address any issues that arise.

Key findings

  • Gradual Volume Increase: Gradually increasing sending volume from the new IP is essential for establishing a positive sending reputation.
  • Phase Out Old ESP: It's crucial to gradually phase out the old ESP while warming up the new IP.
  • Consistent Sending Reputation: Maintaining a consistent sending reputation is vital for preventing deliverability issues.
  • Avoid Sudden Changes: Sudden changes in sending volume should be avoided to ensure deliverability.

Key considerations

  • Monitor Deliverability: Start with small volumes to closely monitor deliverability and address any potential issues.
  • Responsible Sending Practices: Gradual increases demonstrate responsible sending practices to ISPs.
  • Stable Reputation: Gradual adjustments are preferred for maintaining a stable sending reputation.
  • Phase-Out Strategy: Develop a strategy for gradually phasing out the old ESP while increasing volume on the new IP.
Technical article

Documentation from Microsoft shares that you should avoid sudden changes in sending volume. Gradual increases and decreases are preferred to maintain a stable sending reputation and ensure deliverability.

June 2023 - Microsoft
Technical article

Documentation from Google Postmaster Tools explains to gradually increase sending volume when starting to send email from a new IP address. Starting with small volumes allows you to monitor deliverability and address any issues that arise.

February 2023 - Google Postmaster Tools
Technical article

Documentation from SparkPost shares that it's crucial to gradually phase out the old ESP while warming up the new IP. This helps maintain a consistent sending reputation and prevents deliverability issues.

December 2023 - SparkPost
Technical article

Documentation from Amazon SES explains that gradual increase in sending volume helps establish a positive sending reputation. Starting with a low volume and gradually increasing it over time demonstrates responsible sending practices to ISPs.

January 2024 - Amazon Web Services