Summary
The importance of plain text email versions for deliverability is complex and multifaceted. While modern email clients primarily support HTML, plain text versions provide critical benefits including enhanced accessibility (screen readers), fallback compatibility when HTML rendering fails or is disabled, and potential mitigation of spam filters. Plain text ensures that a message is conveyed regardless of HTML support or image blocking. It can offer a bump for B2B filters, especially if images are blocked. Although plain text ensures accessibility, HTML can also be read by screenreaders if it’s clean and properly formatted. Balancing HTML with plain text improves overall email deliverability. Using Multipart MIME guarantees that the text is delivered to the users system in the 'best' format for them - whether that be HTML or Plain Text.
Despite these advantages, relying solely on plain text limits branding opportunities and formatting options. The consensus suggests a blended approach using Multipart MIME to include both HTML and plain text versions, therefore maximising deliverability whilst not having to focus on one format entirely.
Key findings
- Accessibility: Plain text improves accessibility for screen readers; however, HTML is also accessible if created correctly.
- Compatibility: Plain text ensures compatibility with older clients and when HTML rendering is disabled.
- Spam Reduction: Plain text version inclusion can help in avoiding spam filters, as some filters look for its presence.
- Image Blocking Bypass: Plain text ensures a message is conveyed when images are blocked.
- MIME Format Vital: Using the multipart MIME format is essential to including both HTML and plain text options.
Key considerations
- Branding Limitations: Plain text alone limits branding options available with HTML.
- Client Rendering: While plain text support is vital, some experts believe nearly no mail client renders the plain text.
- Resource Allocation: Balancing the effort required to create a plain text version against the actual benefits is a vital consideration.
- HTML Support: Ensure proper HTML support and valid HTML to enable its rendering and accessibility correctly.
What email marketers say
9 marketer opinions
The importance of plain text email versions for deliverability is multifaceted. While modern email clients largely support HTML, plain text versions serve as a crucial fallback for accessibility (screen readers), compatibility (older clients or disabled HTML rendering), and spam filter evasion. They ensure that the message is conveyed even if images are blocked or HTML rendering fails. However, relying solely on plain text can limit branding opportunities. A balanced approach, including both HTML and plain text, is generally recommended.
Key opinions
- Accessibility: Plain text versions enhance accessibility for users with screen readers and those with visual impairments.
- Compatibility: Plain text provides a fallback for older email clients or when HTML rendering is disabled.
- Spam Filters: Including a plain text version can help bypass spam filters, as some filters still check for it.
- Image Blocking: Plain text allows recipients to understand the message even when images are blocked.
- Deliverability Bump: Plain text offers a potential deliverability boost, particularly for B2B filters when remote images are off.
Key considerations
- Brand Elements: Relying solely on plain text limits branding opportunities available with HTML.
- Balanced Approach: A balanced approach is generally recommended, where email contains both plain text and HTML versions to ensure that more users are reached.
- Potential Impact: The impact of omitting plain text on deliverability varies, however it is still beneficial to have.
Marketer view
Marketer from Email Geeks shares that plain text emails are really useful for accessibility (screen readers, etc.). They believe the deliverability-specific benefits are minimal these days but might provide a bump for B2B filters if remote images are disabled.
3 Jul 2024 - Email Geeks
Marketer view
Email marketer from Reddit explains that having a plain text alternative ensures that if the HTML doesn't render correctly (due to email client issues), the recipient can still read the message. It’s a fallback for compatibility.
30 Jan 2025 - Reddit
What the experts say
5 expert opinions
Experts have varying perspectives on the importance of plain text email versions for deliverability. Some highlight its role in accessibility, as screen readers can read both text and alt-text (within HTML). Others emphasize that modern email clients often render HTML better than plain text, questioning the necessity of multipart/alternative formats. However, there's agreement that including a plain text part can be helpful, especially for users with text-based email clients or as a fallback when HTML rendering fails. Additionally, some spam filters penalize HTML-only emails.
Key opinions
- Accessibility: Screen readers can interpret both text and alt-text in HTML emails, though other responses indicate plain text benefits screen reader compatibility.
- Fallback Mechanism: Plain text acts as a fallback when HTML rendering is broken or unavailable.
- Spam Filters: Spam Assassin and some other filters penalize emails lacking a plain text component.
- Legacy Clients: Plain text ensures readability in text-based email clients (e.g., pine, mutt).
- Deliverability Boost: Including a text part is good for deliverability and is beneficial for bandwidth conservation.
Key considerations
- HTML Preference: Modern email clients often render HTML better, potentially diminishing the value of plain text.
- Effort vs. Benefit: The effort required to create a plain text version should be weighed against the potential benefits, especially if mechanical conversion is sufficient.
- Accessibility Balance: Ensure that accessibility is addressed effectively, regardless of whether plain text or HTML is prioritized.
Expert view
Expert from Email Geeks recommends having a plain text version at some level. Spam Assassin penalizes HTML-only emails for missing a text part, which could impact filtering tech built on top of SA.
2 Sep 2022 - Email Geeks
Expert view
Expert from Word to the Wise answers that they have seen arguments that having a text part is good for deliverability and can act as a fallback when rendering is broken. They also add the benefits of better accessibility, bandwidth conservation, and the ability to view the email regardless of settings or device.
4 Jun 2023 - Word to the Wise
What the documentation says
4 technical articles
Documentation emphasizes the importance of including a plain text version in emails, primarily through the multipart MIME format. This format allows for both HTML and plain text versions, ensuring that recipients can read the message even if their email client can't render HTML. It also serves as an accessibility aid, augmenting HTML. Plain text's simplicity results in smaller email sizes compared to rich text formats but lacks formatting options.
Key findings
- Multipart MIME: Using multipart MIME is vital for including both HTML and plain text versions of an email.
- HTML Fallback: Plain text ensures recipients can read the message if their email client can't render HTML.
- Accessibility: Plain text alternatives support accessibility when HTML features are unsupported.
- Message Format: The multipart/alternative content type lets systems choose the best format (HTML or plain text) based on the recipient's environment.
- Smaller Size: Plain text results in smaller email sizes.
Key considerations
- Plain Text Limitations: Plain text only supports unformatted text.
- Formatting Options: Plain text format offers no support for bold, italics, or colored fonts.
- Augment, not Replacement: Plain Text is not a replacement for HTML but augments it.
Technical article
Documentation from Litmus explains that using multipart MIME format is vital. This format includes both HTML and plain text versions of your email. If a recipient’s email client can’t render HTML, the plain text version ensures they still receive the message.
25 May 2023 - Litmus
Technical article
Documentation from Microsoft Support explains that plain text format only supports unformatted text (no bold, italics, or colored fonts). However, it results in smaller email sizes. Whereas Rich Text supports text formatting (bold, italics, colored fonts, etc.) and is the default format for Microsoft Outlook.
20 May 2024 - Microsoft Support
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?
Does including a plain text version of an email improve deliverability and conversion rates?
Does plain text email version affect deliverability?
Is it important to include a plain text version in emails?
When are plain text emails needed and which devices still use them?
