Summary
The responses provide a nuanced view on the necessity of multipart/alternative emails. While some experts suggest it's no longer a strict best practice due to improved HTML rendering and potentially poor text version quality, many others advocate for its continued use. Key benefits include enhanced accessibility for screen reader users, improved deliverability by satisfying spam filters, compatibility with older or less capable clients, and ensuring readability when images are disabled. The documentation confirms that multipart messages are a standard method for sending multiple content types within a single email, commonly HTML and plain text.
Key findings
- Accessibility: Provides a text alternative for visually impaired users who rely on screen readers, although some argue screen readers can process HTML effectively.
- Deliverability: Including a plain text version can improve email deliverability as some spam filters analyze the text-to-HTML ratio.
- Client Compatibility: Ensures compatibility with older or less capable email clients that may not fully support HTML rendering.
- Image Visibility: Offers a readable alternative when images are disabled or fail to load; alt text helps when images are disabled.
- Text Version Quality: Automatically generated plain text versions are often of poor quality; this is a key concern.
- Content-Type Control: Multipart allows specific client choice of content-type, such as text/plain when capable, offering optimized display based on client capability.
Key considerations
- Target Audience: Consider the email client preferences and accessibility needs of your target audience when deciding whether to include a plain text version.
- Content Quality: If including a plain text version, ensure it's a high-quality, accurate representation of the HTML content, not just an automated conversion.
- Deliverability Testing: Test email deliverability with and without a plain text version to assess any potential impact on spam scores; individual results may vary.
- Client Variety: Be aware that a segment of users may still use text-only clients, requiring a plain text version.
- Alt Text Usage: If primarily sending HTML, ensure all images have descriptive alt text for users who have images disabled.
What email marketers say
7 marketer opinions
The consensus is that sending multipart/alternative emails, which include both HTML and plain text versions, remains a beneficial practice. The primary reasons cited are improved accessibility for users with disabilities (especially those using screen readers), enhanced deliverability (due to spam filters analyzing the text-to-HTML ratio), support for older or less capable email clients that may not render HTML properly, and ensuring readability even when images are disabled.
Key opinions
- Accessibility: Providing a text part enhances accessibility for visually impaired users relying on screen readers, ensuring they can understand the email's content.
- Deliverability: Including a plain text version can improve email deliverability as some spam filters analyze the text-to-HTML ratio.
- Client Compatibility: Multipart emails ensure compatibility with older or less capable email clients that may not fully support HTML rendering.
- Image Visibility: Provides a readable alternative when images are disabled or fail to load, especially important when utilizing alt text.
Key considerations
- Spam Filters: Be aware that spam filters may analyze the text-to-HTML ratio, so ensure the plain text version is a meaningful representation of the HTML content.
- Alt Text: Make sure to use alt text on images, so if users have images turned off they can still understand the content of the images.
- Relevance: The plain text version should accurately reflect the content of the HTML version to maintain consistency and avoid misleading recipients.
- HTML Rendering: Though most modern clients support HTML rendering make sure that content has alt text to improve user understanding.
Marketer view
Email marketer from Campaign Monitor shares that HTML is good but alt-text can help a user understand the content of an email if they have images turned off.
11 Feb 2025 - Campaign Monitor
Marketer view
Email marketer from Reddit responds that alt text is essential because if a user can't load images they still understand your content because of the alt text.
14 Jan 2023 - Reddit
What the experts say
5 expert opinions
The provided answers present a mixed perspective on the continued necessity of sending multipart/alternative emails. While some experts argue that it's no longer a strict best practice, citing improved HTML rendering capabilities of modern email clients and poor quality of generated text versions, others emphasize the importance of plain text versions for accessibility, spam filtering, and compatibility with text-only clients. Choosing the correct content-type priority is also mentioned as a way to theoretically cater to different client capabilities.
Key opinions
- HTML Rendering: Modern email clients generally render HTML well, reducing the need for a plain text alternative in many cases.
- Screen Reader Support: Screen readers can often interpret HTML directly, diminishing the need for separate text versions, however in practice this isn't always true.
- Text Version Quality: Automatically generated plain text versions are often of poor quality, potentially degrading the user experience.
- Text-Only Clients: A segment of users still relies on text-only email clients, requiring a plain text version for readability.
- Spam Filtering: Spam filters may analyze the plain text version, making its inclusion potentially beneficial for deliverability.
- Content Type Priority: You can specify content-type priority to prefer text/plain where possible
Key considerations
- Target Audience: Consider the email client preferences and accessibility needs of your target audience when deciding whether to include a plain text version.
- Content Quality: If including a plain text version, ensure it's a high-quality, accurate representation of the HTML content. Don't let tools autogenerate it.
- Accessibility: If a specific client isn't able to load images, consider if alt-text is a better route.
- Deliverability Testing: Test email deliverability with and without a plain text version to assess any potential impact on spam scores.
Expert view
Expert from Email Geeks shares that you can choose your content-type priority in multipart/alternative so theoretically you can send text/plain for MUAs that can render it and text/html for the rest.
16 Jun 2024 - Email Geeks
Expert view
Expert from Spam Resource explains that including a plain text version alongside HTML is still recommended. They state that many email clients will display the plain text version if they cannot render HTML, and spam filters often analyze the plain text version.
29 Jun 2023 - Spam Resource
What the documentation says
3 technical articles
The documentation sources uniformly describe multipart messages as a method for including multiple, related data types within a single email. This is achieved using the Content-Type header to define the different parts and their respective media types. A common application is sending both an HTML and a plain text version of the same content to ensure compatibility across different email clients.
Key findings
- Content-Type Header: The Content-Type header is crucial for specifying the media type of each part within a multipart message.
- Multiple Related Items: Multipart messages enable the inclusion of multiple, related items within a single email, such as HTML and plain text versions.
- Compatibility: Sending both HTML and plain text versions is a common practice to ensure compatibility with various email clients.
Key considerations
- Correct Implementation: Ensure the Content-Type header is correctly formatted and that the boundaries between parts are properly defined to avoid rendering issues.
- Use Case: Determine if a multipart message is necessary for the specific use case. Simple messages with only HTML content may not require it.
- Content Relationship: The different parts of a multipart message should be related to each other, such as alternative representations of the same content.
Technical article
Documentation from Oracle Help Center shares that multipart MIME messages are helpful when you want to send a message with multiple, related parts. This could be an HTML message and a plain text alternative for compatibility.
27 Jul 2022 - Oracle Help Center
Technical article
Documentation from Mozilla explains that multipart messages are useful for sending multiple, related items in a single email. For example, to send an HTML version and a plain text version.
22 Jun 2023 - Mozilla
Are image-based emails a good practice, and what are the deliverability and accessibility implications?
Are there any ISPs or email clients that only accept text emails and reject HTML emails?
Can images in emails cause them to go to spam?
Do images in emails affect deliverability?
Does including a plain text version of an email improve deliverability and conversion rates?
Does plain text email version affect deliverability?
