Summary
Multiple email opens for a single contact are a multifaceted issue influenced by user behavior, technology, and privacy measures. Recipients accessing emails on multiple devices (phone, tablet, desktop) or using different email clients (Apple Mail, Yahoo, etc.) each trigger separate open registrations. Email tracking mechanisms rely on downloading an invisible image; this process is vulnerable to inaccuracies from image blocking, preview panes, and email client settings. Apple's Mail Privacy Protection (MPP) further complicates matters by pre-loading email content, inflating open rates irrespective of actual user engagement, and masking IP addresses. Additionally, security software (firewalls, spam filters) scanning emails, proxy servers, calendaring systems, and forwarding practices can generate non-human-initiated opens. This collective impact renders open rates an unreliable metric for gauging genuine user engagement.
Key findings
- Multiple Devices & Clients: Recipients using multiple devices or email clients contribute to multiple open counts.
- Apple MPP's Impact: Apple's MPP pre-loads content, distorting open rates as genuine engagement indicators.
- Tracking Mechanics & Inaccuracies: Image-based tracking is susceptible to image blocking, preview pane triggers, and email client configuration issues.
- Non-Human Opens: Security software, proxy servers, and calendaring apps can trigger opens without user interaction.
- Email Types: Different email formats (HTML, Plain Text, Rich Text) can influence open tracking.
Key considerations
- Rethink Open Rate Reliance: Open rates are now a less dependable gauge of engagement due to MPP and automated processes.
- Prioritize Other Metrics: Focus on click-through rates, conversions, and other metrics reflecting more direct engagement.
- MPP's Influence on Stats: Factor in MPP's influence when interpreting deliverability statistics and making data-driven decisions.
- Account for Non-Human Interaction: Recognize that some opens originate from automated systems rather than actual users.
- Test client-side display: Ensure test emails are tested on desktop, mobile and web clients and that the HTML emails and images display correctly.
What email marketers say
10 marketer opinions
Multiple email opens for a single contact can be attributed to several factors, often exacerbated by Apple's Mail Privacy Protection (MPP). Recipients accessing emails on multiple devices or across different email clients each register as individual opens. MPP further complicates tracking by pre-loading email images, falsely inflating open rates regardless of actual engagement. Other influences include email security software scanning emails, proxy servers, and email forwarding.
Key opinions
- Multiple Devices: Recipients opening emails on different devices (phone, tablet, desktop) or email clients each generate a unique open.
- Apple MPP Impact: Apple's Mail Privacy Protection pre-loads email images, inflating open rates even if the email is not read by the recipient.
- Security Software: Email security software, such as firewalls and spam filters, may open emails to scan them, generating additional open events.
- Proxy Servers: Multiple opens can be caused by proxy servers between the user and the internet.
Key considerations
- MPP Distortion: Be aware that MPP significantly reduces the reliability of open rates as an accurate engagement metric.
- Focus on Other Metrics: Prioritize other engagement metrics such as click-through rates and conversions, as open rates may be misleading.
- Email Tracking Downsides: Consider if your email client is auto loading images when an email is opened.
- Email Security: Realize that some email security providers might open your mail for scanning and not from human interaction.
Marketer view
Email marketer from StackExchange suggests that multiple opens may come from a proxy server between the user and the internet; or the recipient forwarded the email to another party. It depends if the opens are within seconds of each other.
22 Jul 2024 - StackExchange
Marketer view
Email marketer from Campaign Monitor explains that multiple opens could be due to the recipient opening the email on various devices or email clients or due to email security software pre-loading images to scan the email for security threats. These pre-loads are registered as opens.
13 May 2024 - Campaign Monitor
What the experts say
6 expert opinions
Multiple email opens for a single contact can stem from several sources. The recipient may open the email on multiple devices with varying MPP behaviors. Apple's Mail Privacy Protection (MPP) skews open tracking by pre-fetching content, making opens an unreliable engagement metric. Additionally, non-human actors like proxy providers, or calendaring apps might trigger opens. Thus, it is possible to see multiple opens on one device or across multiple devices.
Key opinions
- Multiple Devices & Prefetching: An email may be opened on multiple devices, some of which prefetch email content, triggering an open even if the user hasn't actively viewed it.
- MPP Impact: Apple's Mail Privacy Protection changes open tracking fundamentally, pre-fetching mail impacting the reliability of engagement metrics.
- Non-Human Opens: Proxy providers or other systems opening email for various reasons can trigger opens separate from user interaction.
- Device Specific MPP: MPP operates on a per-device basis.
- Other Mail Clients: Various mail clients can affect MPP, or other mail clients or webmail may not use any proxy affecting open tracking.
Key considerations
- Reliability of Opens: Opens are not a reliable engagement metric due to MPP and other factors.
- Focus on Other Metrics: Consider other engagement metrics (clicks) for a more accurate representation of engagement.
- Non-Human Interaction: Not all opens are the result of human interaction.
Expert view
Expert from Spam Resource explain that some opens are not from humans. An email message might have multiple opens based on different proxy providers opening the mail or forwarding that might be occurring. This can occur instantly when a mail is sent which is impossible by a human.
18 May 2023 - Spam Resource
Expert view
Expert from Email Geeks shares that calendaring and task management systems sometimes sniff through inboxes.
18 Feb 2023 - Email Geeks
What the documentation says
4 technical articles
Multiple email opens are tracked due to the mechanism of open tracking which relies on downloading an invisible image in the email. This can be impacted by image blocking, preview panes, email client settings and Apple's Mail Privacy Protection (MPP). MPP impacts tracking by pre-loading email content, impacting the reliability of open tracking. Also, the type of email type (HTML, Plain Text or Rich Text) can change how opens are registered.
Key findings
- Open Tracking Mechanism: Open tracking relies on embedding a small, invisible image in the email that is downloaded when the email is opened.
- Factors Affecting Accuracy: Image blocking, preview panes, and email client settings can lead to inaccurate open tracking.
- MPP Impact: Apple's Mail Privacy Protection (MPP) impacts the reliability of open tracking by pre-loading email content.
- Email Type: The type of email (HTML, Plain Text or Rich Text) can change how opens are registered.
Key considerations
- Accuracy of Open Tracking: Be aware that multiple factors can impact the accuracy of open tracking.
- MPP Impact on Deliverability Stats: Understand how Apple MPP impacts your deliverability stats.
- Focus on accurate tracking: The design of emails is HTML and images are not blocked.
Technical article
Documentation from Oracle details how an open is registered in several different email types - plain text, rich text or HTML. HTML mail opens rely on an invisible image downloaded when the mail is viewed.
22 Sep 2023 - Oracle
Technical article
Documentation from SendGrid shares that open tracking relies on a small, invisible image embedded in the email. When the recipient's email client downloads the image, it registers as an open. Multiple downloads (or pre-fetches) will register as multiple opens.
2 Jan 2025 - SendGrid
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