Should I split email sends to engaged users for better deliverability?
Matthew Whittaker
Co-founder & CTO, Suped
Published 2 Jul 2025
Updated 19 Aug 2025
7 min read
The idea of segmenting your email sends, particularly by engagement level, often comes up in discussions about improving email deliverability. The thought is that by sending to your most engaged audience first, the positive metrics generated from that initial, smaller send will somehow 'prime the pump' or provide a boost to your sender reputation, making subsequent sends to less engaged users more likely to land in the inbox.
Specifically, the concept suggests sending an email to your highly engaged subscribers, waiting a short period (like 30 minutes), and then sending the same content to the rest of your list. The rationale is that the high opens and click-through rates (CTRs) from the first batch will signal to Internet Service Providers (ISPs) that your emails are valuable, thereby increasing the chance of the second, larger send bypassing spam filters.
While this strategy seems intuitively appealing, the reality of how ISPs evaluate sender reputation and deliverability is more nuanced than a simple 'piggyback' effect. Let's delve into whether this approach truly works and what factors are genuinely at play.
The perceived logic behind splitting sends
The core of this strategy rests on the understanding that positive engagement metrics, such as opens, clicks, and replies, significantly influence your sender reputation. When recipients interact positively with your emails, ISPs interpret this as a sign that your content is desired and relevant. Conversely, high bounces, spam complaints, and low engagement signal negative intent, leading to poorer deliverability.
Marketers who advocate for this method believe that by front-loading the positive signals with an engaged segment, they can create a favorable impression that carries over to the subsequent, larger send. This could be particularly tempting if you have a significant portion of your list that is less engaged or even unengaged, and you are concerned about their impact on your overall inbox placement.
Some senders who have historically struggled with list quality or opted-in consent might see this as a way to mitigate risks. It's a method born from the desire to leverage immediate positive feedback to counteract potential negative signals from a broader audience, aiming to trick the system into better deliverability.
Why splitting sends might not work
While the intention behind splitting sends to leverage initial engagement is understandable, it's largely an unnecessary and often ineffective tactic. ISPs like Google and Yahoo evaluate sender reputation based on a comprehensive, ongoing history, not just the performance of a small, recent batch of emails.
The 'piggyback' theory
The belief that an ISP will see positive engagement from a small initial segment and apply that positive reputation to a subsequent, larger send within minutes.
Impact on sender reputation
This method aims to artificially inflate reputation signals by isolating high-performing segments.
ISP reality
ISPs analyze billions of data points over time. A 30-minute delay between two identical content sends is unlikely to create a noticeable distinction or provide a significant reputational boost.
Holistic reputation management
Your sender reputation is built on consistent, long-term behavior across your entire sending volume. Artificially splitting sends doesn't address underlying issues with a less engaged audience. As Google states, frequent spam reports from your domain increase the likelihood of future messages being marked as spam.
Furthermore, if you remove your most engaged users from a larger send, the remaining segment will naturally have lower engagement metrics. This could potentially *harm* your deliverability for that larger segment, as ISPs will see a higher ratio of unengaged recipients, negating any perceived benefit from the initial send. It's a zero-sum game or even a net negative if not managed carefully.
The importance of overall list health
Instead of focusing on short-term tactics like splitting sends, the emphasis should always be on fundamental, long-term deliverability practices. Your overall list health is paramount. Sending to unengaged contacts can indeed hurt your overall deliverability, as lower open rates signal to ISPs that your emails are less relevant, as noted by email marketing professionals on Reddit.
List hygiene: Regularly clean your email list to remove inactive or invalid addresses. This prevents bounces and reduces the chances of hitting spam traps. Maintaining a clean list is a core deliverability best practice.
Engagement segmentation: Instead of a rapid split, genuinely segment your list based on engagement over time. Send your most frequent and valuable content to highly engaged subscribers, and consider less frequent, highly targeted campaigns or re-engagement efforts for inactive segments. You can learn more about this in our article, How does email segmentation improve deliverability.
Content quality: Always strive to send relevant, valuable, and engaging content. This is the primary driver of positive recipient interaction.
Authentication: Ensure your email authentication protocols (SPF, DKIM, DMARC) are correctly configured. These are critical for building and maintaining trust with ISPs. Our simple guide to DMARC, SPF, and DKIM can help.
Focus on the overall quality of your email program, rather than attempting to manipulate short-term engagement signals. A strong sender reputation is built on consistent positive interactions from your entire audience over time.
Views from the trenches
Best practices
Maintain a consistently clean and validated email list to prevent hitting spam traps and reduce bounce rates.
Segment your audience based on actual engagement levels and tailor content accordingly, rather than using artificial splits.
Prioritize sending emails to genuinely opted-in and engaged subscribers to build a strong, positive sender reputation over time.
Common pitfalls
Attempting to game the system with short-interval, split sends, believing it will fool ISPs into better deliverability.
Neglecting the overall health of your email list by continuously sending to unengaged or problematic addresses.
Over-relying on quick fixes instead of implementing foundational deliverability best practices.
Expert tips
Implement a robust re-engagement strategy for inactive subscribers, but be mindful of the potential deliverability impact.
Monitor your engagement metrics closely over time using tools like Google Postmaster Tools.
Ensure all email authentication protocols (SPF, DKIM, DMARC) are correctly set up and monitored.
Marketer view
Marketer from Email Geeks says they have heard this type of recommendation in the past and it does seem to work for some senders, but it is unnecessary if you are sending mail recipients have actually asked for and want.
2020-01-28 - Email Geeks
Marketer view
Marketer from Email Geeks says that the ISP is not going to know it's a different send if you do it closely enough.
2020-01-28 - Email Geeks
Sustainable deliverability strategies
Instead of attempting to influence ISPs with a quick, sequential send, focus on genuine, long-term strategies. True email segmentation involves sending messages that are highly relevant to different groups of your subscribers based on their interests, demographics, or past interactions. This natural relevance leads to higher engagement, which in turn organically boosts your sender reputation.
For subscribers who haven't engaged in a while, consider a dedicated re-engagement campaign. This should be a strategic effort to win them back, not an attempt to include them in regular sends that could drag down overall metrics. You can also explore how to manage deliverability when re-engaging inactive subscribers.
It's also crucial to monitor your sender reputation proactively. Utilize tools like Google Postmaster Tools and your email service provider's analytics to identify any dips in engagement or increases in complaints that could signal underlying issues. Understanding these metrics will guide you toward more effective long-term strategies, rather than relying on short-sighted tactics.
Key takeaways
While the idea of splitting email sends to engaged users first might seem like a clever trick to boost deliverability, it's generally not an effective long-term strategy. ISPs are sophisticated and look at your overall sending behavior and list quality, not just the performance of a small, rapidly sent batch. A 30-minute interval is unlikely to create any meaningful difference in how your emails are perceived.
Focusing on building and maintaining a healthy, engaged email list through consistent list hygiene, genuine segmentation, valuable content, and robust email authentication will yield far better and more sustainable deliverability results. Your sender reputation is a marathon, not a sprint, and it's earned through consistent, positive sending practices across your entire audience.
Google and 
Yahoo evaluate sender reputation based on a comprehensive, ongoing history, not just the performance of a small, recent batch of emails.
