Which audience should I move first when swapping ESPs?

It is generally recommended to begin by migrating your most engaged audience first. These are subscribers who have recently opened or clicked your emails, or made a purchase, usually within the last 3-6 months. Their positive interactions help to establish a strong sender reputation on the new ESP's infrastructure.

Do I need to move unsubscribed people to the new ESP?

Yes, you should always migrate all unsubscribed contacts to your new ESP immediately. This is crucial for compliance with email regulations and to prevent accidentally emailing individuals who have opted out, which can lead to spam complaints and blocklistings (or blacklistings). Forgetting this step can severely damage your new sending reputation. For more on this, read about whether to mail unengaged users .

How should I handle unengaged subscribers when switching ESPs?

For unengaged users (those who haven't interacted in 6-12 months), consider a re-engagement campaign from your old ESP, if possible. If not, introduce them slowly and in small segments to the new ESP after your primary warm-up phase. For contacts who haven't engaged in over 18 months, it's often best to remove them from your list entirely, as they pose a higher risk of being spam traps or causing complaints.

Will migrating ESPs affect my sender reputation?

Yes, maintaining your sender reputation is a key goal during an ESP migration. Your new ESP will use new IP addresses, so a proper IP warm-up strategy , starting with your most engaged audience, is essential to build trust with ISPs and ensure consistent deliverability. This also applies to your domain reputation .

When swapping ESPs, what audiences should you move over? - Sender reputation - Email deliverability - Knowledge base

Migrating to a new Email Service Provider (ESP) is a significant undertaking that goes beyond simply transferring data. One of the most critical decisions you will face is determining which audiences to move and when. This choice directly impacts your email deliverability and overall sender reputation.

A strategic approach to audience migration is essential for maintaining a strong sender reputation and ensuring that your emails continue to reach the inbox. It’s not just about getting everyone onto the new platform, but doing so in a way that signals positive engagement to Internet Service Providers (ISPs).

The foundation of your new sender reputation

When you transition to a new ESP, your sending reputation with ISPs essentially begins anew on their infrastructure. This means that the initial emails you send from the new platform are critical in establishing trust. ISPs observe how recipients interact with your first sends to gauge your sending practices.

Prioritizing your most engaged audience members is paramount during this phase. Their positive interactions, such as opens and clicks, serve as strong signals to ISPs like

Google and

Yahoo, indicating that your emails are valued. This process is crucial for effective IP warm-up and establishing a solid sender reputation.

Defining "engaged" typically includes individuals who have opened or clicked an email recently, made a purchase, or otherwise interacted with your brand within the last three to six months. This segment is most likely to provide the positive engagement signals necessary to build trust with a new ESP quickly.

Handling unengaged and unsubscribed contacts strategically

An often-overlooked yet critical first step in an ESP migration is transferring all unsubscribed contacts. Failing to do so can lead to significant compliance issues and recipient frustration.

Always import unsubscribes first

Failing to import your full list of unsubscribed users from your previous ESP to your new platform can result in emailing individuals who have explicitly opted out. This not only creates a poor customer experience but can also lead to spam complaints, blocklistings (or blacklistings), and legal repercussions, potentially harming your new sender reputation.

For unengaged users (those who haven't interacted in six to twelve months), a phased approach is best. Consider running re-engagement campaigns from your old ESP, if possible, or migrate these audiences in smaller, carefully managed segments to the new ESP after the initial warm-up phase. It’s often best to clean your email list by removing contacts who have shown no engagement for over a year.

It's also vital to consider the financial implications of carrying over inactive contacts. Most ESPs bill based on list size, meaning you could be paying for "dead weight" that provides no return and potentially hurts your sender reputation.

Strategic audience migration for deliverability

A successful ESP migration isn't just about moving data, it's about preserving the hard-earned trust with ISPs. A well-executed strategy focuses on the gradual introduction of audience segments to build a positive reputation on the new platform.

Engaged audience (active 0-6 months)

Initial focus: Begin your sending with this segment to establish early trust.
Volume: Start with smaller daily volumes and gradually increase.
Benefit: High engagement helps build a strong sending reputation quickly.
Risk: Low, if segmented correctly and warmed up properly.

Unengaged audience (active 6-12 months or more)

Later phases: Introduce this segment only after a solid reputation is built.
Volume: Send in very small batches, or run re-engagement campaigns first.
Benefit: Potential to reactivate dormant subscribers with careful re-engagement.
Risk: High, can lead to spam complaints and blocklistings if not handled carefully.

Leveraging historical engagement data from your previous ESP is crucial. This data allows you to create precise segments for the gradual warming process and ensure you continue to target recent opens and clicks effectively. It's about maintaining continuity in your communication strategy, even with a new provider.

Your domain reputation is closely tied to how you manage your audience during this transition. Even if you're keeping the same sending domain, the IP address your new ESP uses will be new to ISPs. A strategic migration minimizes any negative impact on your domain's standing. For more on this, check a guide on switching ESPs without damaging deliverability.

Technical considerations and ongoing hygiene

Beyond audience selection, ensure all technical configurations are correctly implemented with your new ESP. This includes DNS records like SPF, DKIM, and DMARC. Proper authentication helps ISPs verify your identity as a legitimate sender, which is crucial for deliverability.

Regularly monitoring your sender reputation through tools like Google Postmaster Tools or

Suped's blocklist monitoring is critical. This allows you to identify and address potential issues early, preventing major deliverability problems and ensuring you don't end up on a blacklist (or blocklist).

Throughout the migration and beyond, list hygiene remains paramount. Continually clean your email list by removing hard bounces, inactive subscribers, and spam traps. This proactive approach supports healthy deliverability and reduces the risk of landing on a blocklist (or blacklist).

A successful ESP migration involves careful planning across multiple departments, from marketing to technical teams. It's a complex project that requires attention to detail and ongoing oversight. For further insights into successful migration, consider checking out this detailed guide on factors for successful ESP migration.

Views from the trenches

Best practices

Start with your most engaged audience to build a strong sending reputation quickly.

Gradually introduce less engaged segments in small batches after initial warm-up.

Clean your email list thoroughly, removing very old and inactive contacts.

Common pitfalls

Forgetting to import unsubscribed contacts, leading to compliance issues.

Migrating an entire unsegmented list at once, risking high bounce and complaint rates.

Ignoring the financial cost of carrying over a large number of unengaged subscribers.

Expert tips

Leverage historical engagement data from your old ESP for precise segmentation.

Monitor your sender reputation closely using tools to identify issues early.

Ensure all DNS records, including SPF, DKIM, and DMARC, are correctly configured.

Expert view

Expert from Email Geeks says: Start with your most engaged audience when moving to a new ESP. This helps build a positive sender reputation from the outset.

Feb 1, 2020 - Email Geeks

Marketer view

Marketer from Email Geeks says: Before moving any inactive audience, consider running re-engagement campaigns. Some contacts might respond on the new platform.

Feb 1, 2020 - Email Geeks

Navigating your ESP migration

Migrating to a new ESP is an excellent opportunity to refine your email program and improve deliverability. However, it demands a thoughtful and strategic approach to audience management.

By strategically moving your most engaged audiences first, carefully handling unengaged segments, and prioritizing the transfer of unsubscribed contacts, you set the stage for strong deliverability and sustained success on your new platform. Remember, a clean, engaged list is your greatest asset.