What are the best practices for sunsetting inactive email subscribers according to ISPs and GDPR?
Michael Ko
Co-founder & CEO, Suped
Published 17 Jul 2025
Updated 17 Aug 2025
8 min read
Managing inactive email subscribers is a critical aspect of maintaining strong email deliverability and a healthy sender reputation. However, the practice of sunsetting these subscribers sometimes clashes with legal interpretations of data privacy regulations, such as GDPR. This presents a unique challenge for email marketers.
On one hand, Internet Service Providers (ISPs) like Google Apple and Yahoo heavily penalize senders with low engagement, leading to emails landing in the spam folder or even outright rejection. On the other hand, legal departments sometimes interpret the tracking of inactivity as profiling under GDPR, which might require specific consent not always obtained during initial sign-up.
The ISP perspective on inactive subscribers
From the perspective of ISPs, consistently sending emails to unengaged recipients signals poor sender quality. When subscribers rarely open or click your emails, or worse, mark them as spam, it negatively impacts your sender reputation. ISPs use engagement as a key metric to determine whether your emails are valuable to their users. Low engagement rates can lead to your domain or IP address being flagged, potentially resulting in your emails being redirected to the spam folder or placed on a blacklist (or blocklist).
These recommendations aren't just suggestions, they are critical for maintaining a positive relationship with mailbox providers and ensuring your messages reach the inbox. Ignoring them can lead to significant deliverability issues, hurting your ability to communicate with even your active subscribers. A clean list is a sign of a responsible sender.
The goal is to foster a positive sender reputation that signals to ISPs that your emails are valued by recipients, making them more likely to deliver your mail to the inbox, rather than the spam folder.
Microsoft: While not as explicit as Google, their focus on low complaint rates and high engagement indirectly points to the need for inactive subscriber management. Maintaining a clean list helps achieve these goals.
General: Most major ISPs look for positive engagement metrics as a strong indicator of wanted mail. Sending to dormant accounts inflates your list size without increasing engagement, which can lead to negative sender reputation over time.
GDPR and the definition of profiling
Navigating the GDPR while performing list hygiene can feel like walking a tightrope. GDPR, or the General Data Protection Regulation, focuses on the protection of personal data and grants individuals control over their information. A key principle is data minimization, which states that personal data should be adequate, relevant, and limited to what is necessary in relation to the purposes for which they are processed (GDPR Article 5(1)(c)).
The concern from legal teams often stems from the interpretation of tracking email engagement (opens, clicks) as profiling under GDPR, which typically requires explicit consent if it leads to automated decision-making with significant legal effects. However, simply identifying inactive subscribers to remove them from your mailing list for deliverability purposes generally does not meet the criteria for profiling as defined by GDPR.
In fact, retaining personal data that is no longer necessary for its original purpose (i.e., sending commercial campaigns that are not being engaged with) could be seen as a violation of GDPR's storage limitation principle (Article 5(1)(e)). If the purpose is to communicate with subscribers, and they are no longer engaging, then continuing to hold and process their data for that purpose might not be legitimate.
It is crucial to clarify that removing inactive subscribers is a measure to maintain list quality and adhere to sender best practices, not to analyze or predict individual behavior for other purposes. This distinction is vital in discussions with legal teams. Effectively, you are removing them so you won't be targeting them, which aligns with privacy principles.
Deliverability needs
Sender reputation: ISPs monitor engagement heavily. Low engagement from inactive subscribers leads to poorer sender reputation.
Spam traps: Old, inactive addresses can become spam traps, causing severe blocklisting issues.
Resource efficiency: Sending to unengaged users wastes resources and inflates costs with your Email Service Provider.
GDPR compliance considerations
Profiling vs. segmentation: Identifying inactivity is usually for list management, not automated decision-making with legal effects. This is distinct from GDPR's definition of profiling.
Data minimization: GDPR encourages holding only necessary data. If a subscriber is inactive, continuing to hold their data for marketing purposes may not be justified.
Legitimate interest: Maintaining a good sender reputation is a legitimate interest, which supports processing data for deliverability purposes.
Developing your sunset policy
Developing a robust sunset policy involves several stages, ensuring you give inactive subscribers every opportunity to re-engage before final removal. First, define what constitutes an inactive subscriber. This definition should be based on engagement metrics such as opens, clicks, or recent purchases over a specific period, typically 3 to 12 months, depending on your sending frequency. This is often an internal standard, but there are resources to help you define unengaged subscribers.
Once identified, these segments should enter a re-engagement campaign. This is a series of emails specifically designed to re-ignite their interest. These campaigns can offer exclusive content, discounts, or simply ask if they still wish to receive your emails. It is a good practice to clearly communicate that if there's no response, they will be removed from the list. If you need help, we have an entire article on how to re-engage inactive email subscribers.
For those who still don't respond after the re-engagement efforts, the final step is to suppress or remove them from your active mailing list. This ensures you're only sending to an engaged audience, which boosts your sender reputation and reduces the risk of hitting spam traps. Keep a suppression list of these addresses to ensure you never email them again, respecting their (implied) preference not to receive your communications.
This systematic approach, known as an email sunset policy, is the best practice for maintaining a healthy and compliant email program. It balances the need for deliverability with data privacy principles, ensuring you respect subscriber preferences while optimizing your email performance. The goal is always to send wanted mail.
Maintains highest level of list hygiene, minimal risk of hitting old spam traps.
Upholds data minimization and rights to erasure, strongest GDPR alignment.
Benefits beyond deliverability
Beyond the immediate benefits to deliverability and GDPR compliance, implementing a sunset policy offers several strategic advantages. A smaller, more engaged email list is more cost-effective. Most Email Service Providers (ESPs) charge based on list size or sending volume, so removing inactive subscribers can lead to direct cost savings.
Furthermore, focusing on an engaged audience allows for more accurate metrics and better campaign planning. Your open rates, click-through rates, and conversion rates will be higher, reflecting the true performance of your email marketing efforts. This accurate data enables better content optimization and strategic adjustments.
A proactive sunsetting strategy enhances your overall email marketing ROI. It ensures your marketing budget is spent on reaching individuals who genuinely want to hear from you, fostering stronger relationships and ultimately driving better business outcomes. This is not just about avoiding penalties, but actively cultivating a healthy and profitable email program. For example, knowing how to increase email click-through rate is made easier with a cleaner list.
This practice also strengthens your brand image. By sending only relevant and desired communications, you demonstrate respect for your subscribers' inboxes and privacy, building trust and loyalty. This positive perception is invaluable in the long run.
Identifying inactive subscribers with a SQL querySQL
/* Example of defining 'inactive' segment logic */
SELECT email_address
FROM subscribers
WHERE last_open_date < DATE_SUB(CURRENT_DATE(), INTERVAL 6 MONTH)
AND last_click_date < DATE_SUB(CURRENT_DATE(), INTERVAL 6 MONTH)
AND is_subscribed = TRUE;
Views from the trenches
Best practices
Regularly segment your email list based on engagement levels to identify inactive users and prioritize re-engagement.
Implement a clear re-engagement campaign strategy before definitive removal from your active mailing lists.
Always honor unsubscribe requests promptly and manage hard bounces immediately to maintain list hygiene.
Ensure your opt-in process explicitly covers tracking for engagement metrics and data processing purposes.
Common pitfalls
Neglecting to define "inactive" clearly, leading to inconsistent list management practices and wasted effort.
Failing to communicate your sunset policy to subscribers, causing confusion or increased spam complaints.
Not understanding that email deliverability directly impacts your sender reputation metrics with ISPs.
Keeping disengaged users on your mailing list, which can attract spam traps and result in blocklisting.
Expert tips
Use your email engagement data to inform legal counsel about the necessity for data retention and processing purposes.
Emphasize that sunsetting aligns with GDPR's data minimization and storage limitation principles for inactive data.
Explain how low engagement can lead to higher spam complaints and increase the risk of being placed on a blocklist.
Leverage management to mediate discussions between marketing and legal on crucial email deliverability practices.
Marketer view
Marketer from Email Geeks says: I cannot see how tracking inactivity meets the criteria of profiling as described in the GDPR, as it is not automated and not based on sensitive personal data.
October 14, 2024 - Email Geeks
Marketer view
Marketer from Email Geeks says: Most organizations implement inactive user management without profiling, so the legal team's perspective seems unusual and may hinder business goals.
October 14, 2024 - Email Geeks
Balancing deliverability and privacy
Sunsetting inactive email subscribers is a fundamental practice for maintaining email deliverability and ensuring compliance with data protection regulations like GDPR. While legal interpretations can sometimes present challenges, the core principle of removing unengaged users aligns with both ISP best practices and the spirit of privacy legislation.
By understanding the perspectives of ISPs and GDPR, implementing a clear sunset policy, and effectively communicating its benefits, email marketers can navigate these complexities. This strategic approach not only optimizes your email program's performance but also demonstrates a commitment to responsible data management and subscriber respect.
Google
Apple
and Yahoo heavily penalize senders with low engagement, leading to emails landing in the spam folder or even outright rejection. On the other hand, legal departments sometimes interpret the tracking of inactivity as profiling under GDPR, which might require specific consent not always obtained during initial sign-up.
Yahoo states that sending emails to users who are not reading them, or who report them as spam, will harm your delivery metrics and reputation, advising senders to monitor inactive recipients. Similarly, 
Apple encourages bulk email senders to manage their subscriber lists so that only engaged subscribers continue to receive emails, specifically mentioning to periodically suppress inactive or disengaged subscribers.
Google: They advise sending messages periodically to confirm that recipients want to stay subscribed and to consider unsubscribing recipients who don't open or read your messages.
Microsoft: While not as explicit as Google, their focus on low complaint rates and high engagement indirectly points to the need for inactive subscriber management. Maintaining a clean list helps achieve these goals.
