Summary
When migrating to a new Email Service Provider (ESP) but keeping the same sending domain and address, it's a common misconception that a warm-up period might not be necessary. While the domain reputation carries over to an extent, the underlying sending infrastructure, including IP addresses, DKIM keys, and sometimes the envelope domain, changes. This shift signals a new sending pattern to mailbox providers (ISPs), necessitating a structured warm-up to establish trust with the new setup and avoid deliverability issues.
Key findings
- IP reputation: Even if you're using a shared IP pool, the specific IPs and their interaction with your sending patterns are new. Mailbox providers learn to associate your domain with these new IPs.
- Authentication changes: New ESPs often mean new DKIM signatures and potentially different envelope domains, which are crucial components of your sender identity. These need to be validated by ISPs.
- Behavioral trust: ISPs monitor sending behavior. A sudden change in IP and sending infrastructure, even with the same domain, can trigger suspicion, leading to throttling or blocklisting. Gradual introduction of volume helps establish trust.
- Reputation is holistic: Sender reputation is a complex blend of factors including domain history, IP reputation, email content, subscriber engagement, and authentication. A shift in any key component requires re-establishment of trust with the new combination.
Key considerations
- Volume and speed: For a volume of around 15,000 emails per day, the warm-up period might be relatively quick compared to higher volumes, but it is still essential. Starting with smaller batches and slowly increasing volume is key.
- List segmentation: Begin warming up by sending to your most engaged subscribers first. This helps generate positive engagement signals (opens, clicks) that are crucial for building a good sender reputation on the new infrastructure. Learn more about retaining sender reputation during ESP migration.
- Monitoring deliverability: Closely monitor your deliverability metrics, including open rates, click-through rates, bounce rates, and spam complaints. Tools like Google Postmaster Tools can provide valuable insights. A comprehensive guide on IP warm up by Twilio SendGrid is a good resource.
- DNS records: Ensure all your DNS records, including SPF, DKIM, and DMARC, are correctly configured for your new ESP before starting to send. Incorrect configurations can lead to emails going to spam.
What email marketers say
Email marketers widely agree that a warm-up period is necessary even when migrating to a new ESP with the same sending domain. While the domain carries its established reputation, the shift to new IP addresses and authentication mechanisms requires a careful ramp-up. Marketers emphasize a cautious approach, often recommending starting with engaged segments and gradually increasing volume to prevent deliverability issues.
Key opinions
- Safety first: Many marketers advocate for a 'better safe than sorry' approach, preferring to warm up even if the exact necessity is debated, as it poses no harm and reduces risk.
- New combination: Reputation is tied to the overall sending configuration (domain, IP, authentication). Changing the IP and authentication components creates a new sending identity that needs to build trust.
- Gradual transition: A gradual transition, sending to engaged segments first, is a widely accepted strategy to mitigate risks during migration.
- Shared IP nuance: While shared IPs have an existing reputation, your specific sending patterns and content interacting with those IPs are new to ISPs. The existing shared IP reputation doesn't fully negate the need for warm-up related to your specific sending profile.
Key considerations
- Engagement first: Prioritize sending to your most active subscribers during the initial warm-up phases. This ensures strong positive signals (opens, clicks) which are vital for building a positive sender reputation on new infrastructure. This is also important for warming up a new domain on an existing IP.
- Monitor feedback loops: Pay close attention to any negative feedback, such as spam complaints or bounces, and adjust your sending volume or strategy accordingly.
- Understand the ESP's warm-up process: New ESPs often have specific recommendations or automated warm-up features. Familiarize yourself with these to ensure a smooth transition, as highlighted by Moosend's guide on warm-up plans.
- Time it right: Plan your migration during a period when you can dedicate resources to monitoring and adjusting your sending, avoiding peak seasons if possible.
Marketer view
Email marketer from Email Geeks explains that even with the same sending domain, a warm-up will be needed because you'll have new IPs, a new DKIM signature, and likely a new envelope domain. While your existing domain reputation helps, the combination of these new factors requires a period of establishing trust.
Marketer view
Email marketer from Quora suggests starting at 5,000 emails per day and safely increasing by 20% daily, while carefully watching for deferrals. This ensures that the new sending infrastructure builds a positive rapport with mailbox providers without overloading them.
What the experts say
Deliverability experts consistently advise that a warm-up period is critical when migrating to a new ESP, even if the sending domain remains the same. Their insights highlight that mailbox providers look beyond just the domain, evaluating the complete sending profile including new IP addresses, DKIM keys, and the interaction of your domain with the new infrastructure. A sudden shift in these elements can be perceived as suspicious, leading to deliverability challenges unless a careful warm-up strategy is employed.
Key opinions
- New IP reputation: Experts confirm that despite using the same domain, a new set of IP addresses requires warming up to build a positive reputation from scratch with ISPs.
- Holistic sending identity: The sender's reputation is built on multiple factors, not just the domain. Changing the underlying sending infrastructure, such as DKIM and envelope domains, creates a new combination that needs to be introduced gradually.
- Risk mitigation: Warming up is a preventative measure to avoid being flagged as spam or getting blocklisted. It allows ISPs to observe consistent, positive sending behavior from the new setup.
- No automatic transfer: Your existing sender reputation doesn't automatically transfer to the new IP space of your new ESP. It must be rebuilt through consistent sending and positive engagement.
Key considerations
- Gradual volume ramp-up: Increase your sending volume incrementally. This allows mailbox providers to build a profile for your new sending setup based on engagement, not just volume spikes. Understanding common deliverability issues during warm-up is crucial.
- Authentication setup: Ensure your SPF, DKIM, and DMARC records are correctly configured for the new ESP. These are fundamental for authenticating your emails and building trust. Spam Resource provides best practices for DMARC reporting.
- Engagement-based sending: Start sending to your most active segments to generate positive engagement (opens, clicks, replies) and minimize bounces or spam complaints, which are detrimental to new reputations.
- Monitor blocklists: Keep a close eye on your IP and domain status on various blocklists (or blacklists) during the warm-up period. Early detection allows for quick remediation if issues arise.
Expert view
Deliverability expert from Email Geeks states that warm-up is definitely needed when migrating to a new ESP. They emphasize that new IPs, a new DKIM signature, and potentially a new envelope domain are all factors that necessitate a warm-up, even with good existing practices.
Expert view
Deliverability expert from Word to the Wise explains that reputation is not solely tied to the domain name. It's a combination of the domain, the IP address, and sending behavior. When you change ESPs, even if the domain is the same, the IP component is new, requiring a warm-up.
What the documentation says
Official documentation from various Email Service Providers and email deliverability resources consistently recommends a warm-up period even when migrating with an existing, reputable sending domain. The core reason is that while domain reputation is crucial, a new ESP introduces new sending IP addresses and potentially new email authentication configurations (like DKIM keys or envelope domains). Mailbox providers monitor these changes closely, and a sudden, un-warmed increase in volume from new IPs can lead to immediate filtering or blocklisting. The documentation stresses the importance of gradually building trust for the new sending infrastructure.
Key findings
- New IP, new reputation: Regardless of domain, new sending IPs must establish their own reputation. This is a fundamental aspect of how mailbox providers assess incoming mail.
- Domain vs. IP warm-up: While domain warm-up is always necessary with a new domain, IP warm-up is required for new IP addresses, even if the domain is established. This distinction is often highlighted.
- Gradual volume increase: The process involves sending low volumes initially and systematically increasing volume over time to demonstrate consistent, legitimate sending behavior.
- Authentication impact: Changes to email authentication (SPF, DKIM, DMARC) associated with a new ESP also play a role and need careful management during the transition.
Key considerations
- Establishing a positive reputation: The primary goal of warm-up is to establish a positive reputation as a legitimate sender from the new infrastructure. Without it, deliverability will suffer. Klaviyo's documentation discusses the importance of warming to establish reputation.
- Monitoring and adjusting: Continuously monitor sending performance (bounces, complaints) and adjust the warm-up schedule as needed. This proactive approach helps in avoiding blacklists and ensuring inbox placement.
- Compliance with best practices: Adhere to general email marketing best practices throughout the migration, such as sending to engaged lists and maintaining clean data. This complements the technical warm-up process.
- Understanding ESP specifics: Each ESP may have slight variations in their recommended warm-up procedures or dedicated tools to assist. Amazon SES provides a comprehensive guide on IP and domain warming.
Technical article
Documentation from OneSignal clarifies that when migrating to a new platform, domain warm-up is always necessary, but IP warm-up is also necessary if you are getting dedicated IPs. Even with a known domain, the new IPs need to establish their reputation with mailbox providers.
Technical article
Documentation from EmailLabs explains that by gradually warming up your sending volume after changes like a new IP address or even new sending patterns with an existing domain, you begin the process of establishing a positive sender reputation. This slow introduction helps prevent emails from being flagged.
Related resources
15 resources
Related pages
What are common email deliverability issues during new IP and subdomain warmup after ESP migration?
What causes emails to go to spam when migrating to a new ESP and warming an IP?
What are the best practices for migrating to a new ESP while retaining sender reputation?
How do you warm up a new sending domain on an existing warmed IP address?
Is it necessary to warm up a domain when migrating to a new ESP?
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