How do embedded interactive forms or AMP in email impact deliverability?

Key findings

• Traditional forms: Direct HTML FORM tags in emails are widely unsupported by email clients and frequently flagged as potential phishing attempts by spam filters, negatively impacting deliverability.
• AMP for email: This technology allows for dynamic, interactive content within the email itself, reducing the need for recipients to navigate to external landing pages. This can lead to higher engagement rates and, consequently, improved sender reputation and deliverability.
• Engagement boost: Interactive elements, when supported, tend to increase user engagement (e.g., higher click-through and conversion rates). Major inbox providers use engagement as a key factor in deliverability, so increased interaction can positively influence your inbox placement.
• Client support: While AMP for Email is gaining traction, it's not universally supported. Gmail, Yahoo Mail, and Mail.ru are notable adopters, but many other clients do not yet render AMP content.

Key considerations

• Fallback content: It is crucial to provide a robust HTML fallback version for recipients whose email clients do not support AMP. This ensures a consistent experience for all users and maintains deliverability for those who won't see the interactive version.
• Security and trust: Spam filters are wary of anything that resembles phishing. Direct HTML forms are a red flag, whereas AMP is designed with security in mind, requiring senders to be reputable to deliver AMP emails. This highlights the importance of maintaining a strong domain reputation.
• User experience: For interactive elements (like forms) that require user data, a common and safer alternative is to embed a link in the email (HTML or AMP) that pre-populates a form on a secure landing page, especially for sensitive or personalized information. This approach is similar to how landing pages impact deliverability generally.
• Complexity: Implementing AMP emails requires additional technical knowledge and careful coding to ensure proper rendering and functionality across supported clients. Poorly coded emails, whether HTML or AMP, can negatively affect deliverability due to malformed HTML. It's essential to understand the AMP for Email specification.

Key opinions

• Avoid HTML forms: Marketers frequently advise against using HTML FORM tags in emails due to poor client support and a high likelihood of being flagged by spam filters as a phishing attempt.
• AMP for engagement: AMP emails are recognized for their ability to significantly increase user engagement by allowing interactions directly within the inbox, such as submitting forms, RSVPing, or reviewing products.
• Client support varies: While AMP is supported by major players like Gmail and Yahoo, many other email clients do not render AMP content, necessitating careful planning for fallbacks.
• Deliverability is engagement-driven: The impact of AMP on deliverability is often indirect, as AMP itself doesn't inherently harm deliverability. Instead, it improves it by fostering higher user engagement, which positive signals inbox providers.

Key considerations

• Fallback strategy: Marketers must design emails with a robust HTML fallback that directs non-AMP users to a web page for interactive content, ensuring no user is left out. This mirrors considerations for image-based emails.
• Data pre-population: For pre-filled forms or personalized content, passing information securely via URL parameters to a landing page is a common and safer practice than embedding it directly in an email FORM tag, especially concerning PII.
• Sender reputation is key: Adopting AMP for email is often reserved for senders with good reputations. Poor deliverability issues may precede successful AMP implementation.
• Measuring impact: Marketers track increased form fill percentages and engagement rates from AMP-enabled recipients as a direct benefit of the interactive experience, which indirectly aids deliverability by signaling positive user interaction to ISPs.

For more on interactive emails, refer to this guide on interactive emails.

Key opinions

• HTML forms are problematic: Using HTML FORM tags in email is strongly discouraged because they are frequently mistaken for phishing attempts by email filters, which will severely impact deliverability.
• AMP's indirect deliverability benefit: AMP emails don't directly improve deliverability, but by increasing user engagement, they generate positive signals for ISPs, which can lead to better inbox placement over time.
• Limited AMP support: Despite its advantages, AMP email is not universally supported by all email clients. This means a significant portion of a recipient list may not experience the interactive content.
• Engagement drives delivery: The fundamental principle remains: if recipients engage with your content, your deliverability improves. AMP facilitates this engagement, but the core relationship is between user interaction and inbox placement.

Key considerations

• HTML fallback essential: Always provide a well-designed HTML version of the email for those who cannot render AMP content, redirecting them to a web page for interactive elements. This is similar to how GIFs impact deliverability if not properly implemented with fallbacks.
• Pre-populated links: Instead of embedding forms, experts suggest using images or links with serialized parameters that pre-populate forms on a landing page, minimizing spam triggers and privacy concerns. This is a general best practice for email content and applies to personalized links as well, similar to how you would structure unencoded URLs.
• Reputation dependency: The successful implementation of AMP for Email is often contingent on a sender already having a good reputation, as ISPs are more likely to display dynamic content from trusted sources. Consider using Google Postmaster Tools to monitor your sender health.
• Security implications: While AMP is designed to be secure, any interactive element requires careful consideration of potential vulnerabilities, especially when dealing with personal identifiable information (PII).

For further insights, a discussion on phishing flags can provide valuable context.

Key findings

• AMP's security model: AMP for Email operates under strict security guidelines, requiring emails to pass specific validation checks to prevent malicious content or phishing. This helps maintain trust with ISPs.
• Engagement metrics: Documentation often emphasizes that higher engagement, driven by interactive content, provides positive signals to inbox providers, which can indirectly lead to better deliverability and inbox placement.
• HTML fallback requirement: All AMP emails must include a valid HTML fallback version for compatibility with email clients that do not support AMP. This is a fundamental requirement to ensure all recipients can view the email content.
• Sender reputation importance: Many providers state that sending AMP emails is primarily available to reputable senders who have established good sending practices, indicating a strong link between sender reputation and the ability to utilize advanced email features.

Key considerations

• Validation process: Senders must undergo a validation process (often involving whitelisting or specific registration) with email providers to send AMP emails, demonstrating adherence to their guidelines.
• Content guidelines: AMP for Email has specific content limitations and supported components. Overly complex or unsupported elements can lead to rendering issues or rejection by the client. This includes general best practices for HTML coding for deliverability.
• User intent: While AMP allows for direct interaction, the intent of the interactive element should align with user expectations and provide genuine value to avoid perceived spamminess. Irrelevant or overly intrusive interactive forms could lead to negative user signals, impacting deliverability.
• Continuous monitoring: Postmaster tools and deliverability metrics should be continuously monitored to assess the impact of AMP emails on user engagement and overall inbox placement, especially in the context of AMP email best practices.