Summary
Consolidating multiple email sending platforms into a single one can streamline operations and improve oversight of your email program. However, successfully migrating and warming up a new IP address, especially after a period of inactivity, is crucial for maintaining and enhancing email deliverability. This process requires careful planning and execution to build trust with Internet Service Providers (ISPs) and avoid deliverability issues such as being routed to the spam folder or encountering a blocklist (also known as a blacklist) listing.
Key findings
- Domain reputation matters: While a new IP offers a fresh start, your domain's historical reputation heavily influences deliverability with many (most) providers. It's essential to understand your current email domain reputation before migration.
- Rewarming IPs: An IP that has been quiet for one to two months typically requires rewarming. Skipping this step can lead to significant deliverability problems, as ISPs expect consistent sending patterns.
- Strategic volume control: The warm-up process involves gradually increasing email volume over time, starting with highly engaged subscribers. This methodical approach demonstrates good sending habits to ISPs, helping to prevent your IP from being perceived as a spam source or getting blocklisted.
- Engagement-first approach: Prioritizing highly engaged audiences, such as welcome flows or triggered emails, during the initial phases of IP warming is a strong strategy. These emails typically have high engagement rates, which positively influence sender reputation.
Key considerations
- Quality over quantity: Focus on the quality of your email list and content. Removing poorly performing emails and audiences from the migration plan can significantly improve deliverability outcomes, as highlighted by Twilio's insights on IP warm-up.
- Consistent sending: Even after the initial warm-up, consistent daily sending helps maintain IP reputation. Irregular sending patterns, especially after a period of dormancy, can trigger spam filters.
- ISP-specific warming: While a general warming plan is good, some ISPs may require specific volume adjustments. Consider tailoring your warm-up schedule to individual ISP requirements. Read more about warming strategies by individual ISP.
- Monitoring and adaptation: Continuously monitor your deliverability metrics, including open rates, bounce rates, and spam complaints, to identify and address any issues promptly during and after the migration.
What email marketers say
Email marketers often face the challenge of migrating email sending infrastructure, whether due to consolidation or switching providers. Their experiences highlight the practical considerations of IP warming and the impact of domain reputation. Marketers frequently seek advice on the best approach to ensure continued high inbox placement rates.
Key opinions
- Initial quality assessment: A common goal for marketers is to understand their overall email quality before consolidating tools. This helps in making informed decisions about which audiences and campaigns to prioritize during the migration.
- Leveraging new IPs: Many marketers view a new IP address within a new Email Service Provider (ESP) as an opportunity for a fresh start, especially if previous sending practices led to deliverability challenges. However, it's vital to pair a new IP with sound sending practices for long-term success.
- Welcome flow for warmup: Using welcome flows or highly engaged triggered emails for the initial warm-up period is a popular strategy. This approach is favored because welcome emails typically generate high engagement, which positively signals to ISPs during the crucial warm-up phase.
- Prioritizing engaged segments: Marketers aim to migrate their most engaged audiences first, leaving behind or scrubbing poorly performing segments. This selective migration helps to establish a strong sending reputation on the new IP from the outset.
Key considerations
- IP rewarming necessity: There can be conflicting advice regarding rewarming an IP that has been dormant. Most marketers acknowledge that an IP inactive for a month or two likely needs to be re-warmed, despite what some providers might suggest.
- Volume control: Even with welcome flows, marketers must be able to cap daily sending volumes. Starting small and gradually increasing sends is paramount to prevent sudden spikes that can trigger spam filters and lead to a blacklist or blocklist listing. More on best practices for email frequency and volume management.
- Budget for support: Hiring external help for IP rewarming might be a budget concern, pushing marketers to seek alternative, self-managed strategies like using highly engaged flows.
- Ongoing monitoring: Even after the initial warm-up, continuous monitoring of email performance and engagement metrics is essential to catch and rectify any emerging deliverability issues, as Knak emphasizes in their IP warming guide.
Marketer view
Email marketer from Email Geeks states they are consolidating from multiple email tools to one, with the primary goal of gaining a clearer understanding of overall email quality. They hope a new IP within their new ESP will help them achieve a fresh start.
Marketer view
An email marketer from Quora suggests that for IP warming, using Google Groups can be effective if you are sending the same email to the same group of people regularly, providing a consistent interaction signal.
What the experts say
Email deliverability experts provide critical insights into IP warming, domain reputation, and the complexities of migrating email infrastructure. Their advice often emphasizes long-term best practices and a cautious approach to volume management, ensuring sustained inbox placement and sender trust.
Key opinions
- Domain reputation is primary: Experts stress that IP reputation is not the sole factor; your domain's historical reputation plays a significant role with most providers. Good practices are crucial for the long term.
- IP rewarming is non-negotiable: If an IP has been dormant for one to two months, experts unequivocally state it needs rewarming, regardless of prior warm-up efforts. Inactivity can quickly erode established trust with ISPs.
- Strategic migration for large senders: For high-volume senders, it is often recommended to migrate highly engaged segments onto a dedicated IP. This approach helps to quickly establish a positive reputation on the new infrastructure.
- Conservative warm-up planning: A conservative warm-up and ramp-up plan is vital, especially when scaling volumes across different ISPs. This helps to manage expectations, control complaints, and minimize unsubscribes.
- Welcome flows can work, with caveats: Using welcome flows for warming can be effective, provided the volume is strictly controlled. It must start very small and gradually increase day by day to mimic organic traffic growth.
Key considerations
- Holistic health check: Before consolidating or migrating, ensure a thorough assessment of your current domain and IP health. This includes checking for any existing email blocklist issues or reputation problems.
- Dedicated IP segregation: For larger senders, consider having separate dedicated IPs for promotional and transactional emails. This allows for better reputation management for distinct email streams. Understanding if a new dedicated IP fixes existing problems is key.
- Authentication protocols: Properly configured SPF, DKIM, and DMARC are fundamental to establishing sender authenticity and should be a priority when setting up new infrastructure. These protocols significantly impact how ISPs perceive your email. More on DMARC, SPF, and DKIM.
- Monitor performance metrics: Pay close attention to engagement, complaint rates, and bounce rates. These metrics are key indicators of your sender reputation and guide adjustments to your sending strategy. Bloomreach's guide on email warm-up offers practical advice.
Expert view
Expert from Email Geeks, who has assisted with consolidations, suggests that while it generally goes well, it requires a strong focus on good practices. Senders should be prepared to significantly reduce volume initially while ISPs become accustomed to the new infrastructure.
Expert view
An expert from Spamresource.com advises that simply acquiring a new IP address does not automatically erase past deliverability issues. The underlying causes of previous problems, such as list quality or content, must be addressed for long-term improvement.
What the documentation says
Official documentation from various email service providers and deliverability experts consistently outlines best practices for IP warming and maintaining sender reputation. These guidelines provide a foundational understanding of how ISPs evaluate incoming email traffic and what actions senders should take to ensure optimal deliverability.
Key findings
- Definition of IP warming: IP warming is defined as the process of gradually increasing the volume of email sent from a new or recently inactive IP address to build a positive sending reputation with ISPs. This establishes the IP as a legitimate sender.
- Importance of sender reputation: Documentation consistently emphasizes that IP warming is key to high email deliverability, building trust with ISPs, improving reach, and increasing inbox placement. A poor reputation can lead to emails landing in spam or being rejected entirely.
- Gradual volume increase: The core principle is to start with small volumes of highly engaged users and progressively increase the sending volume over days or weeks. This allows ISPs to observe consistent, positive engagement.
- Engagement as a trust signal: ISPs track user engagement (opens, clicks, replies) closely. Sending to your most engaged subscribers first helps demonstrate positive user interaction, which is a strong trust signal for the new IP.
Key considerations
- Consistency is vital: Consistent sending volume and frequency are important during and after the warm-up period. Any sudden changes can negatively impact the established reputation. This is one of the common deliverability issues to avoid.
- Monitoring deliverability: Monitoring key metrics such as bounce rates, complaint rates, and spam trap hits is crucial during IP warming. High rates of these indicators can quickly damage reputation and lead to blacklisting.
- Segmenting email types: Some documentation suggests separating transactional and marketing emails onto different dedicated IPs. This allows for distinct reputation management, as transactional emails often have higher engagement rates, as advised by WP Mail SMTP.
- Sender authentication: Ensure that SPF, DKIM, and DMARC are properly configured for your sending domain. These authentication methods are fundamental for ISPs to verify your identity and play a significant role in deliverability.
Technical article
Documentation from Bloomreach explains that email warm-up is the process of building sender reputation for a new email domain or IP address. It is crucial to boost deliverability and avoid spam filters by gradually increasing sending volume.
Technical article
Twilio's blog states that when warming up transactional emails, it is advisable to gradually increase sending volume hourly. This involves a slow migration between your current platform and the new setup, like SendGrid, to ensure smooth transition.
Related resources
7 resources
Related pages
What are common email deliverability issues during new IP and subdomain warmup after ESP migration?
Does a new dedicated IP for transactional emails fix existing deliverability problems?
What are the best strategies for warming email sending IPs by individual ISP?
Best practices for email frequency and volume management after IP warming
Email Deliverability Issues: Getting Your Messages to the Inbox in 2025
Why Your Emails Are Going to Spam in 2024 and How to Fix It
Boost Email Deliverability Rates: Technical Solutions from Top Performing Senders
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A simple guide to DMARC, SPF, and DKIM
