Summary
While it might seem counterintuitive, the presence of AMP code in emails typically does not directly cause increased spam placement in mailboxes like Outlook and Hotmail, even if these providers do not render AMP content. These email clients usually default to the HTML fallback version of the email, and their filtering systems primarily evaluate sender reputation, email content quality, and authentication. A significant drop in open rates or an increase in spam folder placement after implementing AMP, particularly with Microsoft properties, often points to underlying deliverability issues unrelated to the AMP code itself, such as problems with content, sending practices, or authentication.
Key findings
- AMP non-rendering: Outlook and Hotmail do not support AMP for email, meaning they display the HTML fallback version. Therefore, AMP code itself should not directly impact their spam filtering decisions.
- Open rate discrepancies: A perceived drop in open rates for AMP-enabled emails sent to Outlook/Hotmail might be due to inaccuracies in how opens are tracked, rather than actual spam placement.
- Underlying deliverability: If spam placement increases significantly, it’s more likely a sign of deeper deliverability issues related to sender reputation, content quality, or authentication, which affect all email variations.
- Focus on fundamentals: Deliverability success hinges on strong sender practices, content relevance, and proper email authentication (SPF, DKIM, DMARC), regardless of AMP inclusion. You can learn more about how email authentication works.
- Transactional email behavior: Even for transactional emails, a sudden drop in engagement or an increase in spam folder placement should prompt an investigation into changes in sending volume, recipient engagement, or changes to how Microsoft handles high-volume senders.
Key considerations
- Accurate metrics: Rely on metrics beyond opens, such as clicks and conversions, especially when interactive AMP content might reduce direct clicks.
- Content consistency: Ensure the HTML fallback is robust and clean. Any malformed HTML or suspicious elements within the fallback could trigger spam filters.
- Segmentation and testing: Isolate tests to specific domains (e.g., only Microsoft domains) to identify issues more precisely. Consider if your email template changes are affecting Microsoft deliverability.
- Provider-specific analysis: Analyze deliverability data per email service provider (ISP) rather than aggregated numbers. This helps pinpoint where specific problems occur.
What email marketers say
Email marketers often experiment with new technologies like AMP to enhance user engagement. However, when unexpected drops in performance, such as lower open rates or increased spam placement, occur, it raises questions about the direct impact of such code. Marketers frequently rely on open rates as a primary indicator of inbox placement, despite industry advice to consider other metrics. Their experiences highlight the complexities of A/B testing with features like AMP, especially when destination inboxes don't fully support the technology, leading to confusion about the root cause of deliverability issues. They often try to understand why their emails go to spam, even when they appear to have good sender reputations, as they want to avoid emails going to spam.
Key opinions
- Observed performance drops: Marketers report significantly lower open rates (e.g., 30-40% lower) for AMP-enabled emails compared to standard HTML versions, even when sending to providers that don't render AMP.
- Spam placement concerns: The belief is that AMP code, even if not rendered, might influence ISPs like Outlook and Hotmail to mark emails as spam, given observed spam placement rates as high as 100% in some cases.
- Reliance on open rates: Open rates are often used as the primary metric for diagnosing spam placement, despite limitations in their accuracy for measuring inbox placement.
- Positive conversion trends: Despite lower open rates, AMP-enabled emails can still lead to higher conversions, indicating that engaged users are finding and interacting with the emails.
Key considerations
- Transactional email context: For transactional emails from reputable brands, high deliverability is expected, making any drop in performance particularly concerning and indicative of a potential issue.
- Distinguishing issues: Marketers struggle to differentiate between problems with AMP rendering, tracking inaccuracies, and genuine deliverability issues.
- HTML fallback reliance: The fact that non-AMP supporting clients render the HTML fallback means the issue might lie within the HTML structure or content, rather than the AMP section itself.
- Impact on overall strategy: Confusion around AMP's deliverability impact can complicate decisions on whether to adopt AMP for email or focus solely on HTML, as highlighted by discussions around Outlook turning off AMP for email support.
Marketer view
Marketer from Email Geeks identified Outlook and Hotmail as the primary email providers where they observed deliverability problems. This initial assessment pointed towards a specific challenge within Microsoft's ecosystem, suggesting a need for focused investigation into these platforms.
Marketer view
Marketer from Email Geeks reported that their emails were transactional and originated from a large e-commerce brand. They noted that the sender had a strong reputation, boasting 99.8% deliverability for their standard emails, which made the observed issues with AMP-enabled emails particularly perplexing.
What the experts say
Experts in email deliverability consistently emphasize that the mere presence of AMP code in an email is unlikely to cause spam placement issues, especially with providers that do not render AMP. Instead, they highlight that traditional factors like sender reputation, content relevance, and proper email authentication (SPF, DKIM, DMARC) are the primary determinants of inbox placement. They caution against relying solely on open rates as a measure of deliverability, advocating for a holistic approach that includes analyzing clicks, conversions, and provider-specific data. Discrepancies often point to misinterpretations of data or deeper, unrelated deliverability challenges.
Key opinions
- AMP code not the cause: Experts assert that AMP or HTML content alone does not directly impact inbox / spam folder placement. The key factors are sender behavior and recipient engagement.
- Open rate inaccuracy: Open rates are considered flawed metrics for measuring inbox placement, as they rely on image loads and can be affected by pre-rendering or privacy features. Better to understand why deliverability rates can be wrong.
- Focus on clicks and conversions: Clicks are a more reliable metric to gauge email engagement and potential visibility. Higher conversions, despite lower opens, signal success.
- Microsoft's AMP stance: Since Microsoft email clients do not support AMP, emails containing AMP code will render as HTML. Thus, any observed deliverability issues should be attributed to the HTML version or other factors.
- Investigate core issues: When issues arise, experts recommend returning to fundamental deliverability checks, such as sender authentication, shared domain issues, content relevance, and list hygiene. It's important to know why your emails fail.
Key considerations
- Provider-specific analysis: Diagnose deliverability problems by focusing on individual email service providers (ISPs) rather than aggregated data, to identify specific points of failure.
- Authentication review: Ensure proper email authentication protocols (SPF, DKIM, DMARC) are configured correctly, as this is foundational to good inbox placement.
- Content and domain health: Even with AMP in play, look for issues with the HTML fallback or any content elements that might trigger spam filters. Consider the overall health of your sending domain and any shared IP pool effects.
- Avoiding red herrings: Do not chase AMP as a primary suspect for deliverability issues with Microsoft properties, as the technical facts indicate it's likely an unrelated problem. As industry experts suggest, focus on foundational sender readiness.
Expert view
Expert from Email Geeks advised the user to pinpoint the exact providers experiencing issues before drawing conclusions. They stressed the importance of comparing numbers for each service individually, noting that a generalized approach could lead to misinterpretations of deliverability data.
Expert view
Expert from Email Geeks clarified that Microsoft does not support AMP for email. They emphasized that any email sent to Microsoft properties with AMP code would simply render as HTML, making it improbable for the AMP code itself to be the cause of deliverability issues in those specific environments.
What the documentation says
Official documentation from major email providers and industry standards bodies outlines the technical specifications for email rendering and filtering. While AMP for Email is an open-source initiative supported by some major providers like Google, it's explicitly stated that others, including Microsoft, do not support it. This means that for non-supporting clients, the email will always fall back to its HTML version. Therefore, any deliverability issues observed in these environments are governed by the same rules that apply to standard HTML emails: sender reputation, content quality, adherence to email authentication protocols (SPF, DKIM, DMARC), and compliance with the ISP's specific sending policies. The documentation consistently points to these foundational elements as crucial for inbox placement.
Key findings
- AMP non-support: Microsoft (Outlook, Hotmail) does not support AMP for email and has indicated that it will stop or has stopped supporting it completely. This means the AMP part of the email is ignored, and the HTML fallback is displayed.
- HTML fallback crucial: All emails containing AMP must include a valid HTML fallback version. This fallback is what non-AMP supporting clients will render. Deliverability issues in these clients would be related to the HTML content or overall sending practices.
- Sender requirements: Microsoft's new sender requirements for high-volume senders focus on authentication (SPF, DKIM, DMARC), low spam rates, and easy unsubscription. These are general deliverability factors, not specific to AMP.
- No specific AMP blacklisting: There is no documentation from Microsoft or major blocklists/blacklists indicating that the mere presence of AMP code, even unrendered, is a direct trigger for spam filtering or blocklisting.
Key considerations
- Content validation: Ensure the HTML fallback version adheres to best practices and is free of malformed HTML or suspicious content that could trigger spam filters. Understanding how malformed HTML impacts deliverability is critical.
- Authentication standards: Maintain strong email authentication protocols. Providers like Microsoft heavily rely on DMARC, SPF, and DKIM to filter out fraudulent emails.
- Reputation is key: Focus on maintaining a positive sender reputation. Factors like low complaint rates, high engagement, and low bounce rates are crucial. Microsoft's documentation on strengthening the email ecosystem highlights this.
Technical article
Documentation from Microsoft's Tech Community states that by focusing on senders of 5,000+ messages a day, they significantly reduce the likelihood of spam and spoofing campaigns reaching their user base. This indicates that volume and sender trustworthiness are primary filtering criteria.
Technical article
Documentation from Email on Acid confirmed that Microsoft has signaled its intention to completely cease support for AMP for Email, with an update on their Tech Community forum. This confirms AMP's irrelevance for Microsoft-based deliverability.
Related resources
4 resources
Related pages
What email template changes affect Microsoft deliverability and spam scores?
Why are my emails going to the spam folder in Hotmail / Microsoft even with good click to open rates?
Who is using AMP in email and what are the roadblocks?
How do embedded interactive forms or AMP in email impact deliverability?
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