Will Apple MPP or Gmail machine opens occur on emails delivered to spam?
Matthew Whittaker
Co-founder & CTO, Suped
Published 22 May 2025
Updated 18 Aug 2025
8 min read
Understanding how modern email clients handle opens is crucial for anyone involved in email marketing or deliverability. With the introduction of features like Apple Mail Privacy Protection (MPP) and Gmail's own machine-generated open behaviors, the traditional open rate metric has become increasingly complex. A common question I encounter is whether these artificial opens occur even when an email lands in the spam folder (or junk folder). This is a critical distinction, as it impacts how we interpret engagement data and troubleshoot deliverability issues.
My testing and observations suggest a clear answer, which has significant implications for how you analyze your email campaigns and diagnose problems. The way these systems interact with emails depends heavily on the initial inbox placement. Let's delve into the specifics to clarify this common point of confusion.
Apple Mail privacy protection and spam folders
When Apple introduced Mail Privacy Protection (MPP) with iOS 15, it significantly altered how email opens are reported. MPP works by pre-loading email content, including tracking pixels, when an email arrives in the user's inbox. This makes it appear as if the email has been opened, regardless of whether the recipient actually views it. The primary goal is to hide a user's IP address and prevent senders from knowing if and when an email was opened.
The key detail here is the term "inbox." Apple's pre-fetching mechanism is designed to enhance privacy for legitimate emails that successfully land in the primary inbox. If an email is filtered into the spam or junk folder, Apple Mail's MPP (and thus its automated open behavior) typically does not engage. This is because spam folders are usually designed to isolate potentially harmful or unwanted content, and pre-loading images from such emails could pose security risks or simply waste bandwidth on irrelevant content.
This distinction means that if your emails are consistently ending up in the spam folder, you will not see inflated open rates due to Apple MPP for those specific messages. The absence of an MPP-driven open in your data for emails that went to spam is actually a good indicator that they were indeed filtered out, providing clearer signals about your deliverability performance.
Understanding MPP and spam folders
Many email marketers often ask if Apple MPP inflates open rates for emails that land in spam. The answer is generally no. Apple's system is designed to pre-fetch content only for messages that are delivered to the primary inbox, ensuring user privacy for the emails they are most likely to interact with. If an email is classified as spam, it typically bypasses this pre-fetching process, meaning the tracking pixel (and thus the machine open) will not fire.
This behavior helps maintain some level of accuracy for spam classification, as a lack of reported opens from MPP-enabled users might indicate a legitimate inboxing problem rather than just a shift in privacy settings. It means you can still reasonably assume that if you're not seeing MPP-inflated opens, the email might not have reached its intended destination in the inbox.
Gmail machine opens and spam filtering
Gmail also employs its own methods for processing emails, which can result in what are often referred to as "machine opens" or artificial opens. These occur when Gmail's servers scan and cache email content, including images and tracking pixels, for security, anti-spam, and display purposes. This process can sometimes trigger an open event even before a user has actively viewed the email. However, just like with Apple MPP, this behavior is generally limited to emails that are delivered to the user's main inbox.
My testing indicates that the Gmail open pixel typically only fires when a user opens an email in the inbox. Emails that are relegated to the spam folder do not generally generate these machine opens. This aligns with the security posture of most mailbox providers, who aim to minimize interaction with potentially malicious content found in spam.
While there can be rare edge cases where a mailbox provider's (like Gmail's) internal scanning mechanisms might briefly download content before a final spam decision, these are not typically reported back as machine opens in the way that an inbox delivery would. The consistent behavior across these major platforms suggests a shared understanding of how to manage privacy and security in relation to unwanted mail.
Apple Mail Privacy Protection (MPP)
Mechanism:Pre-fetches email content and tracking pixels upon arrival at the Apple Mail app, regardless of the email service (e.g., Gmail, Yahoo).
Spam folder impact:Does not generate machine opens for emails delivered to spam or junk folders. Pre-fetching only applies to messages reaching the inbox.
Purpose: To protect user privacy by hiding IP addresses and preventing precise open tracking for legitimate inbox deliveries.
Gmail Machine Opens
Mechanism:Occur when Gmail's servers scan and cache email content for security and display purposes, primarily for emails in the inbox.
Spam folder impact:Typically, open pixels do not fire for emails that land in the spam folder. This helps prevent tracking for unwanted messages.
Purpose: To enhance security (scanning for malware) and optimize display for legitimate emails, while minimizing interaction with spam.
Implications for deliverability metrics
The fact that neither Apple MPP nor Gmail machine opens occur on emails delivered to spam has significant implications for how we interpret email engagement and diagnose deliverability issues. Before these privacy changes, a low open rate could definitively indicate poor inbox placement. Now, with MPP, a high open rate from Apple users might not mean strong engagement, but a low open rate (or absence of machine opens) from those same users, especially for a segment typically engaging, strongly suggests your emails are going to spam.
This means that while open rates are less reliable for overall engagement, they can still provide valuable signals for spam filtering diagnostics. If you send an email and see virtually no opens from a segment that predominantly uses Apple Mail (and you know your list quality is good), it's a strong indicator of deliverability issues, such as landing on a blocklist or being filtered directly into the junk folder. This is a subtle but important distinction in how we use the metric now.
Instead of relying solely on open rates, focus on metrics that truly reflect active engagement, such as click-through rates (CTR), conversions, and replies. These actions require conscious user intent and are less susceptible to machine-generated activity. Additionally, monitor your Google Postmaster Tools spam rates and domain reputation to get a clearer picture of your overall deliverability health. You should also ensure your email authentication is strong, including SPF, DKIM, and DMARC, as these play a critical role in inbox placement.
Example Apple Mail header indicating client use
X-Mailer: Apple Mail (Version 15.0 (3737))
Adapting your email strategy
As an email sender, you must adapt your strategies to these new realities. While it's reassuring to know that machine opens don't inflate spam folder metrics, it also means that diagnosing deliverability issues requires a more nuanced approach. Instead of solely looking at open rates for engagement, we should view them as one data point among many, especially when trying to understand why emails might be ending up in the junk folder.
Maintaining a healthy sender reputation is more critical than ever. This involves regularly cleaning your email lists to remove inactive or invalid addresses, monitoring your bounce rates, and ensuring your content is relevant and engaging. A robust blocklist monitoring strategy is also crucial, as being listed on a blacklist (or blocklist) will severely impact your ability to reach the inbox, irrespective of MPP or Gmail's behaviors.
Ultimately, the goal remains the same: ensure your emails land in the inbox and provide value to your recipients. By understanding the intricacies of how Apple MPP and Gmail machine opens interact with spam folders, you can make more informed decisions about your email strategy and improve your overall email deliverability.
Views from the trenches
Best practices
Actively monitor other engagement metrics like clicks, conversions, and replies.
Segment your audience by email client to better understand MPP's true impact.
Regularly clean your email lists to remove inactive subscribers, reducing spam trap risk.
Focus on content quality and personalization to drive genuine engagement, not just opens.
Common pitfalls
Over-reliance on open rates as the sole metric for campaign success or deliverability.
Failing to differentiate between MPP/machine opens and actual user engagement.
Neglecting sender reputation and list hygiene, leading to more emails hitting spam.
Ignoring feedback loops from major ISPs which signal spam folder placement.
Expert tips
Implement DMARC reporting to gain deeper insights into your email authentication and delivery.
Utilize Google Postmaster Tools for Gmail-specific insights on spam rates and reputation.
Consider A/B testing different subject lines and preheaders, as these are visible before an open.
Integrate email data with CRM data to see how email engagement correlates with overall customer lifecycle.
Marketer view
Marketer from Email Geeks says content is not downloaded when it goes into the spam or junk folder, so machine opens would not occur in that scenario.
2023-08-03 - Email Geeks
Expert view
Expert from Email Geeks says Apple only prefetches opens for email that was sent to the inbox, confirming the behavior is limited to legitimate deliveries.
2023-08-03 - Email Geeks
Key takeaways
The short answer to whether Apple MPP or Gmail machine opens occur on emails delivered to spam is generally no. Both Apple's Mail Privacy Protection and Gmail's server-side pre-fetching mechanisms are designed to interact with emails that successfully land in a user's primary inbox, not those filtered into spam or junk folders. This behavior is crucial for preserving the integrity of privacy features and avoiding unnecessary processing of unwanted mail.
For email senders, this means that while open rates are less reliable for measuring true engagement due to these privacy features, they can still serve as a valuable indicator for deliverability. If you see a sudden drop in reported opens from Apple Mail users or a general lack of machine opens, it could signal that your emails are facing inbox placement challenges, such as being directed to the spam folder. Prioritizing core deliverability best practices, robust authentication, and focusing on deeper engagement metrics remains key to successful email marketing.
Gmail's) internal scanning mechanisms might briefly download content before a final spam decision, these are not typically reported back as machine opens in the way that an inbox delivery would. The consistent behavior across these major platforms suggests a shared understanding of how to manage privacy and security in relation to unwanted mail.
Gmail's servers scan and cache email content for security and display purposes, primarily for emails in the inbox.
