Will using non-breaking spaces and soft hyphens in email templates affect inbox placement?
Matthew Whittaker
Co-founder & CTO, Suped
Published 5 Jun 2025
Updated 17 Aug 2025
7 min read
When crafting email templates, every detail of the HTML code seems to matter, and rightly so. We meticulously optimize for responsiveness, design integrity, and loading speed. But what about less obvious elements, like non-breaking spaces and soft hyphens? These characters are often used for precise layout control, preventing awkward line breaks or enabling intelligent hyphenation.
The question frequently arises: could the inclusion of such special HTML entities potentially harm your email's deliverability or, more specifically, its inbox placement? It is a valid concern, as email service providers (ESPs) and mailbox providers (MBPs) employ sophisticated algorithms to detect anything that might signal spam or a poor user experience.
While these characters are standard HTML, their excessive or unconventional use might raise an eyebrow, or so some marketers fear. We will explore the technical aspects of non-breaking spaces and soft hyphens, their common applications in email, and whether they truly pose a threat to getting your messages into the primary inbox.
Understanding non-breaking spaces and soft hyphens
A non-breaking space, typically represented by the HTML entity or  , is a character that prevents an automatic line break at its position. This is particularly useful in design to keep specific words or short phrases, such as a number and its unit (e.g., "10 kg"), together on the same line, enhancing readability. In web development, and by extension email template design, it ensures visual consistency across different screen sizes and email clients, where normal spaces might allow unwanted breaks.
Soft hyphens, or ­ or ­, are invisible characters that suggest a potential hyphenation point within a word if it needs to break across lines. Unlike a regular hyphen, a soft hyphen only appears if the word is split. This allows for more aesthetically pleasing text flow, especially in justified text or responsive layouts where word wrapping can be unpredictable, ensuring words are hyphenated correctly without appearing hyphenated when they fit on a single line.
Both characters serve important typographic and layout purposes. However, in the context of email, their presence, especially in large quantities or unusual placements, can sometimes be misinterpreted. HTML standards cover these characters, but email client rendering engines can be notoriously idiosyncratic, often leading to unexpected results or layout mistakes that impact the user experience, rather than deliverability itself.
Email client rendering and spam filters
Email clients (also known as Mail User Agents or MUAs) interpret HTML and CSS differently. While many follow modern web standards, some, particularly older versions or certain desktop clients, might have quirks. Non-breaking spaces and soft hyphens are standard HTML entities and are generally parsed correctly by most major email clients, including Gmail and Outlook. Their primary impact is on visual presentation, not typically on whether an email is flagged as spam.
Spam filters, on the other hand, are designed to identify malicious or unwanted content. They look for suspicious patterns, such as excessive hidden text, obscured links, or high spam complaint rates. While a template filled with redundant or malformed HTML can sometimes contribute to a higher spam score, the characters and ­ themselves are unlikely to be direct triggers for spam classification.
Pre-header hiding code example
One common use case where these characters appear in bulk is in pre-header hiding code. This technique attempts to push unwanted pre-header text out of view in the email client preview. While it can look gross in the code, it is generally benign from a deliverability standpoint. Here is an example:
While this specific code uses a variety of zero-width and spacing characters including and ­, its purpose is for visual manipulation of the pre-header, not for hiding malicious content. Therefore, mailbox providers typically do not penalize it for deliverability. However, it's always wise to test your email templates across different clients to ensure it renders as intended.
Actual impact on deliverability
The consensus among email deliverability professionals is that non-breaking spaces and soft hyphens, when used correctly and in moderation for their intended purpose, do not negatively impact inbox placement. Spam filters are far more concerned with factors like sender reputation, IP address health, content relevancy, authentication protocols (SPF, DKIM, DMARC), and user engagement metrics.
The core issue is rarely the presence of these characters, but rather the overall quality and intent of the email. If your email practices are otherwise sound, a few or ­ characters will not be the reason your email lands in the spam folder. Issues like malformed HTML, excessive hidden text used to keyword stuff, or poor coding practices are far more likely to raise red flags.
The perceived risk
Increased HTML complexity: Some believe that highly complex HTML, even with valid characters, might be viewed suspiciously by filters looking for obfuscation.
Hidden content misinterpretation: Filters might incorrectly flag these characters as attempts to hide text, similar to how spammers hide keywords.
Rendering issues: Inconsistent rendering across clients can lead to a poor user experience, which indirectly impacts sender reputation over time if it leads to complaints.
The actual impact
Negligible on spam filtering: Modern spam filters are too sophisticated to be tripped by standard HTML entities used correctly for formatting.
Primary impact on rendering: The main concern is whether the email displays correctly across all email clients, rather than deliverability.
Indirect reputation risk: Poor rendering can lead to user frustration, potentially increasing unsubscribes or spam complaints, which do affect deliverability.
Best practices for using special characters
While non-breaking spaces and soft hyphens are generally safe, it is always wise to adhere to best practices to ensure optimal inbox placement and a consistent user experience. The goal is to create clean, efficient HTML that renders reliably across all platforms without introducing unnecessary complexity.
Use sparingly: Apply these characters only when absolutely necessary for typographic control. Avoid using them excessively for general spacing, as CSS properties like padding or margin are typically more appropriate and predictable for layout.
Thorough testing: Always test your email across a wide range of email clients and devices. Use an email testing tool to catch any rendering inconsistencies that might arise from these characters or other HTML elements. This is crucial for maintaining a positive recipient experience, which indirectly supports deliverability.
Prioritize authentication and reputation: Focus your efforts on strong email authentication (SPF, DKIM, DMARC), maintaining a clean email list, and sending relevant, engaging content. These factors have a far greater impact on your email deliverability rates than the occasional special character.
Remember, the real deliverability threats often lie in sender reputation issues, content that mimics spam, or poor email list hygiene. While clean code is always preferable, the minor complexities introduced by non-breaking spaces and soft hyphens for their intended layout purposes are generally not significant enough to trigger spam filters or blocklists (blacklist). Focus on the larger picture of email best practices for consistent inbox placement.
Views from the trenches
Best practices
Always test your email template rigorously across various email clients to ensure special characters render as intended.
Use non-breaking spaces and soft hyphens judiciously, only when absolutely necessary for precise typographic control.
Prioritize fundamental deliverability factors like sender reputation, email authentication, and audience engagement.
Common pitfalls
Over-relying on special characters for general spacing instead of appropriate CSS padding or margin properties.
Failing to test how these characters appear in the pre-header area across different email clients, leading to broken previews.
Assuming that visible 'gross' code will automatically trigger spam filters without understanding its actual function.
Expert tips
Consider alternative pre-header management techniques if rendering issues persist or if code cleanliness is a high priority.
Regularly monitor your inbox placement rates and DMARC reports to identify any deliverability issues, which are more often related to reputation than minor HTML entities.
Familiarize yourself with RFCs (Request for Comments) like the MIME specification to understand how email content is technically defined and transmitted.
Expert view
Expert from Email Geeks says that the specific code snippet with non-breaking spaces and soft hyphens is a standard technique for pre-header hiding and generally won't be flagged by mailbox providers.
2024-09-04 - Email Geeks
Marketer view
Marketer from Email Geeks says that while such code might look aesthetically displeasing in the template, its functionality for controlling pre-header content is widely accepted and not typically an issue for deliverability.
2024-09-04 - Email Geeks
The verdict on special characters and inbox placement
In conclusion, the direct impact of using non-breaking spaces and soft hyphens in your email templates on inbox placement is minimal to non-existent. These are standard HTML entities intended for specific layout and typographic purposes. While they might contribute to more complex or 'messy' looking code, modern spam filters are sophisticated enough to understand their function and do not typically flag them as spam indicators.
The main consideration remains visual rendering. Always prioritize thorough testing across different email clients to ensure your emails look as intended. Focusing on your sender reputation, email authentication, and content quality will yield far more significant improvements to your deliverability than worrying about these particular characters.
Gmail and 
Outlook. Their primary impact is on visual presentation, not typically on whether an email is flagged as spam.
