Summary
Transitioning to a new ESP while maintaining sends on your current platform and using the same domain requires a strategic and phased approach. A consensus emerges on the importance of using separate subdomains for each ESP, specifically for the envelope 'from' or bounce domain, to ensure proper bounce handling and SPF alignment. Unique DNS records, particularly SPF and DKIM, are essential for each ESP's subdomain. Experts emphasize the need for gradual IP warm-up, starting with small segments of engaged subscribers and closely monitoring key metrics like open rates, bounce rates, and spam complaints. Maintaining synchronized lists, running ESPs in parallel, A/B testing campaigns, and establishing feedback loops with email providers are also critical. Finally, proper configuration of SPF, DKIM, and DMARC records and consistently alerting email providers help ensure ongoing deliverability.
Key findings
- Subdomain Isolation: Using different subdomains for the envelope 'from' address (bounce domain) is essential for proper bounce handling and SPF alignment with multiple ESPs.
- Unique DNS Records: Each ESP requires its own SPF and DKIM records, configured for its corresponding subdomain.
- Gradual IP Warm-up: A phased IP warm-up process, starting with small, engaged segments, is crucial for building a positive sender reputation.
- Synchronized Lists: Maintaining synchronized lists across both ESPs, especially suppression lists, is critical to avoid deliverability issues and legal complications.
- Importance of Monitoring: Continuous monitoring of key metrics (open rates, click-through rates, bounce rates, spam complaints) is essential for identifying and addressing deliverability problems.
- SPF Configuration: SPF records should include the appropriate 'include:' statements for each ESP to ensure proper authentication.
Key considerations
- Visible 'From' Address: While different subdomains are needed for the envelope 'from,' the same domain or subdomain can generally be used in the visible 'from' address.
- Parallel Sending: Running both ESPs in parallel allows for comparison of performance and a gradual transition of email volume.
- A/B Testing: A/B testing campaigns across both ESPs can identify any performance differences and help optimize the transition.
- Feedback Loops: Establishing feedback loops with email providers is essential for monitoring and addressing deliverability issues.
- Domain Reputation: Proactively manage and monitor your domain reputation, especially with key mailbox providers like Gmail, using tools like Google Postmaster Tools.
- DNS Propagation: Allow enough time for changes in DNS records to fully propagate before launching large email sends.
- Notify Providers: Alerting email providers with who you're now working with (new ESP) makes sure their systems get the right message about a new surge of emails from your company, as they're now using a different ESP.
What email marketers say
8 marketer opinions
Transitioning to a new ESP while maintaining sends on your current platform requires a strategic approach to avoid deliverability issues. Key steps include using different subdomains for the new ESP to prevent DNS conflicts, gradually warming up the new domain, replicating suppression lists across both ESPs, and closely monitoring performance metrics. Running ESPs in parallel, synchronizing lists, and A/B testing campaigns can provide valuable insights. Ensuring proper SPF record configurations with include statements for each ESP is also crucial.
Key opinions
- Subdomain Isolation: Utilize different subdomains for the new ESP to avoid DNS conflicts and allow for gradual warm-up without impacting the primary domain's reputation.
- Gradual Warm-Up: Gradually warm up the new domain by starting with low volumes and increasing sends over time to build a positive sender reputation.
- List Replication: Replicate suppression lists across both ESPs to avoid sending to unsubscribed users during the transition.
- Parallel Sending: Run both ESPs in parallel, splitting the email list to compare performance and gradually shift traffic to the new ESP.
- SPF Records: Configure SPF records with include statements for each ESP to ensure proper authentication and prevent deliverability issues.
Key considerations
- Monitor Metrics: Closely monitor key metrics such as open rates, click-through rates, and bounce rates on both ESPs to identify and address any deliverability issues.
- Synchronize Lists: Maintain synchronized lists to ensure that unsubscribe requests are promptly reflected across both ESPs.
- A/B Testing: A/B test email campaigns on both ESPs to identify performance differences and optimize results.
- Reputation Management: Be aware of the domain and ip reputation on both services.
Marketer view
Email marketer from StackOverflow emphasizes the importance of using include: statements in the SPF records as each ESP will have a different authentication domain. This will help email services identify your company's domain.
5 Apr 2022 - StackOverflow
Marketer view
Email marketer from Email on Acid emphasizes maintaining synchronized lists. Ensure that unsubscribe requests are promptly reflected across both ESPs. Failing to do so may hurt your reputation and cause legal issues.
21 Jun 2024 - Email on Acid
What the experts say
8 expert opinions
Transitioning to a new Email Service Provider (ESP) while maintaining sends on your current platform, using the same domain, requires careful management of subdomains, SPF records, and IP warm-up. Experts recommend using the same domain/subdomain in the visible 'from' address but different subdomains in the envelope 'from' address to ensure proper bounce handling by each ESP. Each ESP should have its own SPF record, reflecting its unique bounce domain. A phased approach to IP warm-up is crucial, especially without dedicated IPs, involving small batches of recipients and close monitoring of performance metrics. It's important to establish feedback loops with email providers and ensure DNS records are accurate.
Key opinions
- Subdomain Differentiation: Use different subdomains for the envelope 'from' address (bounce domain) for each ESP to enable correct bounce processing.
- SPF Records per ESP: Each ESP must have its own SPF record, aligning with its unique bounce domain (e.g., esp1.domain.com).
- IP Warm-up: Handle IP address warm-up gradually, especially without dedicated IPs, by sending to small batches of recipients and monitoring performance.
- Visible From Address: The same domain or subdomain can be used in the visible 'from' address across ESPs.
- DKIM Subdomains: Using different subdomains in the d= for DKIM is recommended.
Key considerations
- DNS Records: Ensure all DNS records (SPF, DKIM, DMARC) are correctly configured for each ESP and subdomain.
- Feedback Loops: Enable feedback loops with email providers to monitor and address deliverability issues.
- Performance Metrics: Closely monitor performance metrics like bounce rates and spam complaints during the transition.
- Consistent Sending: Maintain consistent sending practices to preserve reputation.
- SPF Alignment: Ensure that the SPF record aligns with the bounce domain to maintain deliverability.
Expert view
Expert from Email Geeks defines SPF Domain as the Envelope From / Return Path / Bounce domain / 5321.from. The end user does not see this domain unless they go look for it. It is the domain that is checked by SPF and the one that must match the Visible From domain for DMARC to pass. It does not need to be a domain controlled by the sending entity. Defines Visible From domain as what most non-email-geek people think of as the From domain. This is what is visible to the end user when they read their mail (assuming their mail client doesn’t hide it like all too many of them do). This is what consumer filters use to help drive delivery to individual user inboxes. This is the domain that is verified by DMARC.
11 Jan 2022 - Email Geeks
Expert view
Expert from Word to the Wise recommends using different subdomains for the envelope from address (the bounce domain) when using multiple ESPs simultaneously. This ensures that each ESP can handle bounces correctly and maintains proper SPF alignment. You can, however, use the same subdomain in the visible from address.
20 Mar 2025 - Word to the Wise
What the documentation says
5 technical articles
Transitioning to a new ESP while maintaining sends on an existing platform and domain requires careful planning, particularly around DNS configuration, IP warming, and reputation management. Key recommendations from documentation include setting up separate subdomains for each ESP, ensuring unique SPF and DKIM records, and gradually warming up the new IP address by sending to engaged subscribers. Monitoring sender reputation and engagement metrics is crucial, as is ensuring proper configuration of SPF, DKIM, and DMARC records to maintain deliverability, especially with Gmail.
Key findings
- Subdomain Isolation: Separate subdomains for each ESP are recommended to avoid DNS conflicts and maintain distinct authentication settings.
- Unique DNS Records: Each ESP needs unique DNS records, particularly SPF and DKIM, configured for its respective subdomain.
- IP Warmup is Essential: Gradually warm up the new IP address and domain by starting with low volumes sent to highly engaged subscribers.
- Sender Reputation Matters: Maintaining a positive sender reputation is crucial for email deliverability, especially with mailbox providers like Gmail.
- Authentication Configuration: Proper configuration of SPF, DKIM, and DMARC records is essential for all sending domains and subdomains.
Key considerations
- Monitoring: Continuously monitor sender reputation and engagement metrics to identify and address deliverability issues.
- Feedback Loops: Set up and monitor feedback loops to understand how mailbox providers are viewing your email traffic.
- Engagement: Focus on sending to engaged subscribers during the IP warmup process to establish a positive sending reputation.
- DNS Propagation: Allow sufficient time for DNS record changes to propagate fully before initiating significant email volume from the new ESP.
- Google Postmaster Tools: Utilize Google Postmaster Tools to monitor domain and IP reputation specifically for Gmail users.
Technical article
Documentation from SendGrid emphasizes the importance of IP warmup. Start by sending low volumes of emails to your most engaged subscribers and gradually increase the volume over time. This helps build a positive sender reputation with mailbox providers.
16 Jun 2024 - SendGrid
Technical article
Documentation from Amazon Web Services suggests setting up separate subdomains for each ESP you intend to use. This allows you to maintain separate SPF and DKIM records for each, avoiding conflicts and ensuring proper authentication. Each subdomain should handle its own bounces and feedback loops.
14 Aug 2022 - Amazon Web Services
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