Is a plain text email version important for email deliverability?
Michael Ko
Co-founder & CEO, Suped
Published 12 Jul 2025
Updated 16 Aug 2025
7 min read
When crafting emails, especially for marketing or transactional purposes, a common question arises: how important is the plain text version for email deliverability? We often focus on the visual appeal and rich formatting of HTML emails, but the underlying structure and alternative text versions play a critical role in ensuring our messages reach the inbox.
The concept of a plain text email version comes from the multipart/alternative MIME type. This standard allows an email to contain multiple versions of the same content, usually an HTML version for visual display and a plain text version for clients that cannot render HTML or for accessibility purposes. Email clients then choose the most appropriate version to display to the recipient.
While some might argue its diminishing importance in an HTML-dominant world, the plain text version still holds weight in the complex landscape of email delivery. Ignoring it can have subtle, yet impactful, consequences on how your emails are perceived by spam filters and, ultimately, whether they land in the inbox.
Why the plain text version matters
The primary reason a plain text version remains important for email deliverability is its interaction with spam filters and older or specialized email clients. Many spam filtering technologies, like Spam Assassin, factor in the presence and quality of the plain text part when scoring an email. An email that is only HTML, without a corresponding plain text version, can sometimes accumulate negative points, increasing its spam score.
This doesn't necessarily mean your email will go straight to spam, especially with major inbox providers like Gmail or Outlook. These providers often have sophisticated filtering mechanisms that rely more on sender reputation, content relevance, and engagement metrics. However, for smaller email providers or corporate networks that might still use older filtering systems, the lack of a plain text version can indeed lead to deliverability issues. This is why some sources confirm plain text emails can have higher deliverability rates.
It’s about mitigating all possible risks. Even if the impact is minimal for some recipients, why take the chance? Ensuring a plain text alternative provides a fallback, preventing your emails from appearing as raw HTML code or, worse, being outright blocked by certain configurations. We discuss this in more detail when we consider how a plain text email version affects deliverability.
Accessibility and fallback for all email clients
Beyond deliverability, a plain text version significantly enhances accessibility. Screen readers used by visually impaired individuals often struggle with complex HTML structures, especially if not coded with accessibility in mind. A clean, well-formatted plain text version ensures that the core message is conveyed clearly and efficiently.
Think about users accessing emails on older mobile devices, text-only email clients, or those with strict security settings that disable HTML rendering. Without a plain text alternative, these users might see a blank message, broken images, or incomprehensible code, leading to a poor user experience. While it's true that tracking opens and clicks can be harder with plain text, its importance for overall reach cannot be overstated.
Furthermore, a plain text version acts as a crucial fallback. If your HTML email has rendering issues, or if an email client decides to block the HTML content for any reason, the plain text version is what the recipient will see. This is particularly relevant for emails that are heavily image-based, where the absence of a text version could mean a completely empty or unreadable message.
The good news is that most modern email marketing platforms automatically generate a plain text version based on your HTML content. While this automated process is convenient, it's not always perfect. URLs might appear messy, formatting can be lost, and the overall readability might suffer. This highlights the importance of checking and, if necessary, manually optimizing your plain text version.
For platforms where manual creation is time-consuming, like Marketo mentioned in a discussion, it presents a challenge. The perceived minimal deliverability consequences might not justify the significant build time. However, a balance can be struck. Mechanical conversion that results in an unreadable plain text message should prompt a review, perhaps not of the plain text specifically, but of the underlying HTML structure that makes it difficult to convert cleanly.
The goal is to ensure that even the stripped-down version of your email makes sense and conveys the essential information clearly. This contributes to overall email health and deliverability, even if it's a subtle factor.
Automated generation pitfalls
URL readability: Auto-generated plain text often shows full, unformatted URLs, which can look messy and be difficult to read, especially for long tracking links.
Formatting loss: All HTML formatting (bold, italics, headings, lists) is removed, which can impact the hierarchy and emphasis of your message. This is why it's crucial to understand how email code quality affects deliverability.
Content context: Images are replaced by alt-text, but the surrounding text needs to provide sufficient context without the visual cues.
HTML vs. plain text: a balanced approach
While HTML emails offer rich visual experiences, plain text versions contribute to a robust deliverability strategy. The choice isn't always about one over the other, but ensuring both are present and optimized. Many experts agree that including a plain text version is a best practice, even if its direct impact on major inbox providers is not as pronounced as it once was. You can find out more about the general topic by reading our article on the importance of including a plain text version.
Ultimately, the effort invested in a well-crafted plain text version is a small price to pay for increased accessibility and reduced risk of hitting spam filters, especially the more sensitive ones. It's an essential component of a comprehensive email strategy that prioritizes reaching every possible recipient.
Consider the following comparison to highlight the key differences and benefits:
HTML emails
Visual appeal: Allows for rich design, images, branding, and interactive elements. Ideal for marketing campaigns and newsletters.
Tracking: Easier to track opens and clicks through embedded pixels and unique URLs.
Compatibility: Supported by most modern email clients, but rendering can vary significantly across clients and devices.
Plain text emails
Simplicity: No formatting, images, or styling. Focuses solely on the message content.
Deliverability: Less likely to trigger certain spam filters, especially older ones. Crucial as a measure to avoid spam folders.
Accessibility: Highly compatible with screen readers, text-only clients, and devices with limited capabilities.
Views from the trenches
Best practices
Always include a plain text version in your multipart/alternative emails.
Review the auto-generated plain text version to ensure it is readable and conveys the core message.
Optimize links in the plain text version for clarity and user-friendliness.
Common pitfalls
Sending HTML-only emails without any plain text fallback.
Relying solely on automated plain text generation without manual review.
Ignoring the impact of missing plain text on niche or older email clients and spam filters.
Expert tips
Consider a more personal, text-based approach for certain email types, like transactional messages.
Leverage alt-text effectively in your HTML emails, as screen readers can utilize it.
Focus on clean HTML code that simplifies the plain text conversion process.
Expert view
Expert from Email Geeks says a plain text part is useful for accessibility, particularly for screen readers. They believe the deliverability benefits are minimal, but note there might be an advantage for B2B filters if remote images are disabled at an organizational level.
2023-04-06 - Email Geeks
Marketer view
Marketer from Email Geeks says they still recommend a plain text part because Spam Assassin (a common anti-spam tool) penalizes HTML-only emails that lack a text part. They acknowledge this may not affect major domains like Google and Yahoo but could impact others built on Spam Assassin's technology.
2023-04-06 - Email Geeks
Final thoughts on plain text emails
While the direct deliverability impact of a plain text email version might be less significant with major email providers today compared to a decade ago, it is still a crucial component for a holistic email strategy. It addresses accessibility concerns, acts as a reliable fallback for diverse email clients, and avoids potential negative scoring by certain spam filters, particularly the lesser-known ones or those on corporate networks.
The effort involved in creating and maintaining a decent plain text version is a small investment for the peace of mind it offers, knowing your message has the best possible chance of being delivered and read by every recipient, regardless of their email client or settings. Always aim for a well-rounded approach to your email content, including a thoughtfully prepared plain text alternative, to ensure optimal email deliverability.
Gmail or 
Outlook. These providers often have sophisticated filtering mechanisms that rely more on sender reputation, content relevance, and engagement metrics. However, for smaller email providers or corporate networks that might still use older filtering systems, the lack of a plain text version can indeed lead to deliverability issues. This is why some sources confirm plain text emails can have higher deliverability rates.
