How to warm up email sending after migrating to a new ESP with the same domain and shared IPs?

Summary

Migrating to a new ESP, even with the same domain and shared IPs, requires a comprehensive IP warming strategy. Experts, marketers, and documentation sources agree that the new ESP's IPs should be treated as 'new,' necessitating a gradual warm-up to establish a positive sending reputation. This process involves a phased approach, starting with highly engaged subscribers and incrementally increasing the volume while closely monitoring deliverability metrics like bounce rates, spam complaints, and sender reputation. Engaging in consistent communication with mailbox providers and carefully monitoring sender reputation with tools like Google Postmaster Tools and Microsoft SNDS are vital for maintaining optimal deliverability.

Key findings

  • Treat IPs as New: The shared IPs provided by the new ESP should be treated as new, irrespective of the existing domain reputation.
  • Gradual Warm-up: Implement a gradual IP warming strategy to introduce the new sending profile to ISPs and mailbox providers.
  • Engagement is Key: Focus initial sending efforts on highly engaged subscribers to build a positive reputation.
  • Monitoring Metrics: Closely monitor essential metrics like bounce rates, spam complaints, and overall sender reputation.
  • DKIM impact: Changes to DKIM signing domain during migration can impact deliverability, necessitating a warming period.
  • Communication Matters: Warmup is about building a new line of communication and trust with mailbox providers, not just volume.

Key considerations

  • Phased Approach: Adopt a phased approach to IP warming, gradually increasing sending volume over a defined period.
  • Segmentation: Segment email lists to identify and prioritize the most engaged subscribers for initial sends.
  • Feedback Loops: Actively monitor feedback loops and address any deliverability issues promptly.
  • Monitor Sender Reputation: Continuously monitor sender reputation using tools like Google Postmaster Tools and Microsoft SNDS.
  • ESP Expertise: Consult the new ESP's recommendations for warming up IP, as they possess more data and best practices.

What email marketers say
9Marketer opinions

When migrating to a new Email Service Provider (ESP) even with the same domain and shared IPs, a warm-up process is essential. The consensus is to treat the new ESP's shared IPs as new, irrespective of existing domain reputation. A phased approach, focusing initially on the most engaged subscribers, is recommended, gradually increasing volume. Close monitoring of deliverability metrics like bounce rates, spam complaints, and sender reputation through tools like Google Postmaster Tools is crucial. Moreover, a change in DKIM signing domain can also affect delivery, necessitating a warm-up.

Key opinions

  • New IPs: The new ESP's shared IPs should be treated as new, requiring a warm-up even with a pre-existing domain reputation.
  • DKIM Impact: A change in the DKIM signing domain when migrating to a new platform necessitates a warm-up.
  • Engagement Focus: Start by sending emails to the most engaged subscribers to build a positive reputation with ISPs.
  • Gradual Increase: Gradually increase the sending volume over several days or weeks, following a structured IP warm-up strategy.
  • Monitor Metrics: Closely monitor deliverability metrics such as bounce rates, spam complaints, and sender reputation using tools like Google Postmaster Tools.

Key considerations

  • Segmentation: Segment your email list and start the warm-up process with your most active and engaged contacts.
  • Deliverability Monitoring: Continuously monitor email performance, including bounce rates and spam complaints, to identify and address any issues promptly.
  • Sender Reputation: Keep a close eye on your sender reputation, using tools like Google Postmaster Tools and Microsoft SNDS, to ensure your emails are being delivered.
  • List Hygiene: Maintain a clean email list by removing inactive or disengaged subscribers to improve deliverability.
  • Content Quality: Send high-quality, relevant content to your subscribers to encourage engagement and avoid spam filters.
Marketer view

Email marketer from Email Marketing Forum explains that the shared IPs in the new ESP are 'new' to your domain. The poster recommends gradually increasing volume, and carefully monitoring deliverability. Pay special attention to hard bounces, and complaints. Keep the lists clean.

December 2024 - Email Marketing Forum
Marketer view

Email marketer from Mailchimp advises warming up new IP addresses to build a positive reputation with ISPs, especially when migrating to a new ESP. The recommendation is to start with small batches of emails to engaged subscribers and gradually increase volume over several weeks.

December 2024 - Mailchimp
Marketer view

Email marketer from GlockApps recommends a specific IP warm-up strategy, increasing volume in defined increments over a number of days. This will allow the sender to establish a reputation with the ISPs. This also allows time to monitor deliverability to ensure compliance with sending limits.

August 2024 - GlockApps
Marketer view

Email marketer from Reddit suggests that when using the new ESP's shared IPs, you should treat them as new and follow the recommended IP warming schedules. Monitor sender reputation metrics closely using tools like Google Postmaster Tools.

May 2023 - Reddit
Marketer view

Email marketer from ActiveCampaign recommends a phased approach to IP warm-up after migrating to a new ESP, even with a reputable domain. They advise starting with your most engaged subscribers and gradually increasing volume based on positive engagement signals.

July 2021 - ActiveCampaign
Marketer view

Email marketer from EmailOctopus states that warming up is always needed when switching to a new ESP, even with existing domains. Start with a small segment of highly engaged users and scale up sending slowly while monitoring bounce rates and spam complaints.

September 2024 - EmailOctopus
Marketer view

Email marketer from Hubspot outlines the IP warm-up process when you migrate to a new ESP. The marketer notes that you should segment your list, start with your best contacts, send consistently, and monitor your email performance. The recommendation is to send good emails.

April 2023 - Hubspot
Marketer view

Email marketer from GMass shares that when switching ESPs, warming up your IP address is paramount. Start by sending to your most engaged subscribers and carefully monitor your bounce and complaint rates. A slower start will help.

November 2021 - GMass
Marketer view

Email marketer from Email Geeks shares that Google and Yahoo now focus on the DKIM signing domain, which will change when moving to a new platform, requiring a warmup. Offers to share tips based on experience with large warmups.

September 2022 - Email Geeks

What the experts say
6Expert opinions

Migrating to a new ESP, even with an existing domain and shared IPs, requires a warm-up to establish a new domain/IP combination with filters and mailbox providers. This process is about more than just sending volume, it's about communication and building a sending profile. While it can be shorter with shared IPs, following the ESP's advice and starting around 3-5K emails is recommended. Any major infrastructure change requires warm-up.

Key opinions

  • New IP/Domain Combination: Moving to a new ESP creates a new IP/Domain combination, requiring warm-up even with established domain reputation.
  • Infrastructure Changes: Any major change, including new IPs or envelope domains, necessitates a warm-up process.
  • Communication is Key: Warm-up is about establishing communication with mailbox providers, not just sending emails.
  • ESP Expertise: Following the new ESP's advice is recommended as they possess the most current data.

Key considerations

  • Gradual Warm-up: Introduce the new sending profile slowly with a gradual increase in volume.
  • Initial Volume: A reasonable starting point is around 3,000 to 5,000 emails.
  • Step-by-Step Approach: A detailed, step-by-step approach to warming the IP ensures best practices are followed.
Expert view

Expert from Email Geeks explains that moving to a new ESP with the same warmed-up sending domains still requires a warmup to introduce the new domain/IP combination to filters, as this will affect delivery. Resources provided will also help.

January 2023 - Email Geeks
Expert view

Expert from Email Geeks states that any major infrastructure change, including new IPs or envelope domains, necessitates a warmup process.

April 2022 - Email Geeks
Expert view

Expert from Word to the Wise shares advice on warming up email sending at Gmail. Even with a pre-existing domain reputation, you should start slow to establish a new sending profile with Gmail. He suggests a specific gradual volume increase strategy.

July 2024 - Word to the Wise
Expert view

Expert from Word to the Wise suggests that the warmup process isn't just about sending emails. It’s about establishing a new line of communication with mailbox providers after an ESP migration. The author emphasizes the importance of consistent, engaged communication.

September 2024 - Word to the Wise
Expert view

Expert from Email Geeks advises that warmup can be shorter when moving a domain to shared IPs. They recommend following the new ESP's advice, as they have the most data on what currently works. Starting at 3-5K emails is a reasonable approach these days.

December 2023 - Email Geeks
Expert view

Expert from Spam Resource outlines that IP warming is crucial after an ESP migration, even with a good domain reputation. It's necessary to introduce your sending habits from the new IP range to ISPs and mailbox providers. The article details a step-by-step approach to IP warming.

June 2023 - Spam Resource

What the documentation says
5Technical articles

When migrating to a new ESP, even with the same domain and shared IPs, a gradual IP warm-up is crucial to ensure deliverability. The consensus among documentation sources is that a new ESP means new IPs that need to be warmed up, irrespective of existing domain reputation. This involves starting with low volumes and gradually increasing them based on engagement metrics. Crucially, continuous monitoring of sender reputation and deliverability metrics using tools like Google Postmaster Tools and Microsoft SNDS is essential during and after the migration.

Key findings

  • New ESP, New IPs: A new ESP translates to new IPs that require warming up, even with the same domain.
  • Sender Reputation: Maintaining a good sender reputation is key, but a new ESP requires re-establishing trust.
  • Gradual Warm-up: A gradual increase in sending volume is essential to establish trust with mailbox providers.
  • Monitoring Tools: Tools like Google Postmaster Tools and Microsoft SNDS provide valuable insights into deliverability.

Key considerations

  • Engagement Metrics: Base your volume increases on engagement metrics to ensure deliverability.
  • Feedback Loops: Actively monitor feedback loops to address deliverability issues promptly.
  • Continuous Monitoring: Continuously monitor your sender reputation and deliverability to prevent issues.
Technical article

Documentation from Google shares that Google Postmaster Tools provides valuable insights into your domain and IP reputation. Monitor these metrics closely during and after ESP migration to ensure continued deliverability to Gmail users.

April 2023 - Google
Technical article

Documentation from Microsoft SNDS tells that monitoring your IP health in Microsoft's Smart Network Data Services (SNDS) is crucial during and after the ESP migration. This tool provides valuable insights into your sending reputation with Microsoft email services and helps identify deliverability issues early.

October 2023 - Microsoft
Technical article

Documentation from SendGrid explains that even with a good sender reputation, a gradual IP warmup is essential when migrating to a new ESP. Start with low volumes and gradually increase based on engagement metrics to establish trust with mailbox providers.

September 2023 - SendGrid
Technical article

Documentation from SparkPost shares that when migrating to a new ESP, even with an established domain, you need to warm up the new IP address to ensure deliverability. Starting slowly and monitoring deliverability metrics is crucial.

February 2025 - SparkPost
Technical article

Documentation from Postmark emphasizes that even with the same domain, a new ESP means new IPs. You need to warm up those IPs. Monitor sender reputation closely by checking feedback loops to ensure your deliverability remains high.

February 2022 - Postmark