Will iOS Outlook 'Read More' clipping impact email deliverability?

Key findings

• Rendering, not delivery: If an email is clipped, it means it has already reached the recipient's inbox and been opened.
• Pixel limit: Outlook on iOS apps typically clips emails that exceed a height of around 5000 pixels. This is a known technical limitation. Further details can be found in the email-bugs GitHub repository.
• Engagement impact: While not a deliverability issue, clipping can negatively affect subscriber engagement by hiding crucial content or calls to action.
• Similar to gmail: Outlook's clipping behavior is comparable to Gmail's clipping, which also occurs when email size exceeds a certain threshold.

Key considerations

• User experience: Prioritize keeping essential content and calls to action visible above the clipping point to maintain engagement.
• Email optimization: Consider optimizing your email code quality and size to prevent unnecessary clipping, especially for lengthy emails.
• Testing: Routinely test your emails across various devices and email clients, including Outlook on iOS, to ensure proper rendering.
• Deliverability focus: While clipping itself does not affect deliverability, maintaining good sender reputation and avoiding spam complaints are crucial for inbox placement.

Key opinions

• Engagement over delivery: Marketers often perceive clipping as more of an engagement issue than a deliverability one, as the email has already landed in the inbox.
• UX priority: The primary concern is ensuring that recipients see the full message without needing extra clicks.
• Content length impact: Clipping is frequently observed with lengthy newsletters or promotional emails containing a large amount of content.
• Hidden calls to action: A common fear is that calls to action (CTAs) placed too far down in the email might be hidden by the 'read more' link, impacting conversions.

Key considerations

• Above the fold: Design emails to put critical information and primary CTAs within the initial visible screen area, before any potential clipping.
• Content conciseness: Evaluate whether your email content can be more concise to avoid reaching clipping limits, particularly for emails with many elements or links.
• A/B testing: Experiment with different email lengths and designs to see how they perform in terms of engagement metrics across various email clients.
• Client-specific fixes: While Outlook iOS clipping is a known issue, marketers may need to explore client-specific coding workarounds to mitigate it.

Key opinions

• Delivery confirmation: Experts stress that if an email is clipped, it means it was successfully delivered to the inbox and opened. This is a positive deliverability signal.
• No direct deliverability impact: Clipping itself is not considered a negative factor by ISPs for determining whether an email should be sent to the spam folder or rejected.
• User interaction is key: Factors like a user marking an email as spam are far more influential on future deliverability than rendering issues like clipping.
• Focus on core authentication: Maintaining proper email authentication (SPF, DKIM, DMARC) and avoiding issues that cause emails to fail are more critical for deliverability.

Key considerations

• Monitor spam rates: Instead of clipping, closely monitor your spam complaint rates and maintain a healthy sender reputation, as these are direct deliverability indicators.
• Audience behavior: While clipping doesn't hurt deliverability, it can impact whether your audience engages with your messages over time.
• Outlook-specific considerations: Be aware of Outlook and Hotmail's unique filtering mechanisms to proactively prevent deliverability issues, though clipping isn't one.
• Beyond clipping: Ensure your overall email program adheres to best practices for high-volume sending with Microsoft to avoid actual delivery failures.

Key findings

• Defined limit: The Outlook app on iOS is documented to clip emails that exceed approximately 5000 pixels in height.
• Content truncation: Any content extending beyond this pixel limit is hidden and can only be viewed by clicking a 'Read More' button.
• Client-specific behavior: This clipping is a function of the Outlook mobile application itself, rather than a filtering action by the mail server.
• No deliverability flag: Official documentation does not indicate that email clipping is a factor in determining email deliverability or spam scores.

Key considerations

• HTML and CSS efficiency: While not a deliverability issue, optimizing your email's HTML and CSS for compactness can help avoid clipping and improve loading times.
• Image optimization: Large or numerous images contribute significantly to email height, so consider optimizing their dimensions and file sizes.
• Email rendering tests: Utilize email rendering testing tools to preview how your email appears in various clients, including Outlook on iOS, to identify clipping proactively.
• Cross-platform consistency: Strive for a consistent email experience across different devices, acknowledging that some client-specific behaviors like clipping may require design adjustments.