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Summary

The question of whether to send multipart/alternative emails has evolved significantly over time. Historically, it was considered a best practice to ensure compatibility across diverse email clients and to provide a plain text fallback for those unable to render HTML. Today, with advancements in email client technology and screen reader capabilities, the direct impact on email deliverability is minimal. However, its role in accessibility and offering a robust user experience remains a point of discussion. While modern email clients are highly capable of processing HTML, providing a well-structured plain text alternative can still cater to niche cases or specific accessibility tools.

What email marketers say

Email marketers often weigh the historical advice of sending multipart/alternative against the practicalities of modern email campaigns. Many question whether the effort translates into tangible benefits for deliverability or engagement, especially when automated tools generate subpar plain text versions. The general sentiment leans towards focusing on a high-quality HTML email, while recognizing that a well-crafted text version can still enhance accessibility for a segment of their audience, though perhaps not for deliverability directly.

Marketer view

Marketer from Email Geeks suggests that including a plain text version might not directly improve deliverability, leaving the benefit of multipart/alternative in question.

29 Nov 2020 - Email Geeks

Marketer view

Marketer from Email Geeks states that if HTML-only emails are sent to their personal plain-text email client (Pine), it's not their fault if it doesn't render well. This highlights the user's preference for plain text.

29 Nov 2020 - Email Geeks

What the experts say

Email deliverability experts offer a nuanced perspective on multipart/alternative emails. While acknowledging its historical significance as a Best Current Practice (BCP), they largely agree that its direct impact on deliverability has diminished. The focus has shifted from mere presence to the quality of content within both parts, particularly concerning accessibility for screen readers. Experts highlight that a poorly constructed plain text version can be more detrimental than simply sending HTML-only emails, emphasizing that modern email clients and accessibility tools are increasingly adept at handling HTML content effectively.

Expert view

Expert from Email Geeks notes that while they might prefer clients to implement multipart/alternative, its presence or absence does not significantly affect email delivery.

29 Nov 2020 - Email Geeks

Expert view

Expert from Email Geeks states that current best practices for email sending may not always align with what is strictly necessary for deliverability. This suggests a distinction between historical norms and modern requirements.

29 Nov 2020 - Email Geeks

What the documentation says

Technical documentation, primarily RFCs, defines the structure and intent behind multipart/alternative MIME types. These specifications outline how different representations of the same content should be included within an email, allowing email clients to select the most suitable version for display. While the RFCs provide the foundational framework, practical implementation and user agent (email client) behavior often dictate the real-world impact on content rendering and accessibility. The key is ensuring a graceful degradation for recipients, providing a fallback for clients that cannot render the richer HTML version.

Technical article

Documentation from MailPace explains that multipart/alternative signifies that an email contains multiple representations of the same content, each in a different format, typically offering HTML and plain text versions.

22 Mar 2024 - MailPace

Technical article

Documentation from Krystal Labs clarifies that when attaching files, the main Content-Type should be set to multipart/mixed instead of multipart/alternative, distinguishing between providing alternatives and including separate parts.

22 Mar 2024 - Krystal Labs

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