Guide to Email Rendering for Enterprise Marketing Teams

It's a feeling too many of us in marketing operations have experienced before: a screenshot of an email hopelessly broken in Outlook or some other client. Email remains one of marketing's most powerful channels, but it's also the most unforgiving. Poorly rendering emails is like tripping just before you reach the finish line of a race you were about to win.

You can't undo a bad email.

Email rendering issues have long been a thorn in the site of email marketers. Accounting for the sheer number of clients out there and various devices used to access those clients is the stuff of nightmares for developers and designers. For enterprise marketing teams, however, the margin of error is very low. A poorly rendered email can erase all the hard work you put into making a beautiful, engaging email.

In this post, we're going to take a look at email rendering, how to solve challenges, and a way to future-proof your email in the future.

The Hidden Cost of Poor Email Rendering in Enterprise Marketing

When an email renders poorly, it's more than just a visual annoyance. For enterprise organizations, the stakes are particularly high:

Brand Perception Suffers: When customers see broken layouts or missing images, they question your attention to detail. For global enterprises with carefully cultivated brand identities, this inconsistency can erode trust and diminish brand equity built through other channels.

Conversion Rates Decline: Unusable buttons, illegible text, or disrupted flows directly impact response rates. We've seen cases where rendering issues on Outlook can result in precipitous drops in conversions.

Scale Magnifies Problems: What might be a minor problem for a small business becomes exponentially worse at enterprise scale. When sending millions of emails monthly across multiple business units, even a small percentage of rendering failures represents significant lost opportunity.

Understanding the Email Rendering Landscape

Unlike websites that generally render consistently across modern browsers, emails can display in thousands of different ways depending on various factors. This variability creates significant challenges for marketing operations teams working at enterprise scale.

The email rendering journey is influenced by multiple technical layers:

1. Your Email Service Provider (ESP) may alter your code before sending, typically adding tracking pixels and redirecting links
2. The recipient's email client interprets your HTML and CSS according to its rendering engine
3. The device and screen size determine how the layout displays
4. User preferences like image blocking or dark mode further modify appearance

For enterprise teams, these variables multiply across millions of recipients, creating a complex matrix of rendering scenarios.

The Evolution of Rendering Engines

Email rendering has a complicated 50-year history that has led to today's fragmented landscape. Today's enterprise marketers must contend with dozens of different rendering engines, including Apple Mail's WebKit, Outlook's Microsoft Word and Internet Explorer engines, and Gmail's specialized implementations.

This diversity means that a single email can display in up to 15,000 different ways depending on how it's rendered.

How Different Email Clients Render HTML

Understanding how major email clients process your code is essential for troubleshooting rendering issues:

Outlook Challenges: Navigating the Enterprise Email Client Standard

Microsoft Outlook presents perhaps the biggest headache for enterprise email marketers. This is particularly problematic because Outlook remains the dominant client in many corporate environments.

The Word Rendering Engine Problem

Outlook versions from 2007-2019 on Windows desktop use Microsoft Word as the rendering engine, which severely limits HTML email rendering capabilities. This made sense historically when email was text-focused like letter writing, but it creates significant problems for modern HTML emails.

Key limitations in Outlook include:

• No support for background images in <div> tags
• No CSS float or position properties
• Limited support for margin and padding
• Poor handling of animated GIFs (shows only first frame)
• Inconsistent rendering of nested tables

Complicating matters further, Windows users can select 120 DPI (dots per inch) settings to increase screen resolution, which causes desktop email clients to enlarge images and text—potentially breaking carefully designed layouts.

By contrast, Outlook for Mac uses WebKit as its rendering engine, meaning it generally renders emails similar to Apple Mail and iOS devices. This inconsistency between Outlook versions creates additional testing and development requirements for enterprise teams.

Outlook-Specific Solutions

Enterprise teams should implement these specific tactics for Outlook:

1. Use VML (Vector Markup Language) for background images
2. Create "bulletproof buttons" that work across all Outlook versions
3. Implement MSO conditional comments to provide Outlook-specific styling:

<!--[if mso]>

<style type="text/css">

.outlook-specific-class {

color: #000000;

font-weight: bold;

}

</style>

<![endif]-->

Mobile-First Email Design for Enterprise Campaigns

With at least half of all email opens occurring on mobile devices, and a 2024 report indicating that 71.5% of consumers primarily use mobile phones to view emails, mobile optimization is essential. Rather than designing for desktop first and then adapting for mobile (which has been the traditional approach), enterprise teams should consider adopting a mobile-first email design strategy.

This approach involves starting with the mobile experience and then enhancing it for larger screens, which often results in cleaner, more focused designs that work well across all devices. For enterprise marketing operations, this may require updating design systems and processes that have traditionally been desktop-focused.

Mobile-first design principles for enterprise email include:

• Single-column layouts that adapt to multi-column on desktop
• Touch-friendly buttons (minimum 44×44 pixels)
• Larger font sizes (minimum 14px for body text)
• Compressed images optimized for mobile loading speeds
• Focused content that works on smaller screens

Code Practices for Consistent Enterprise Email Rendering

While most email clients now support styles applied to <div> tags, Outlook still doesn't provide consistent support. Therefore, using HTML tables for email structure remains the most reliable approach for ensuring consistent rendering across all email clients. Though this may seem like an outdated practice to web developers, it provides the most consistent experience for email subscribers without causing formatting issues.

HTML Structure Best Practices

• Use HTML tables for layout structure
• Set explicit width attributes on table cells
• Nest tables for complex layouts
• Keep your code simple and clean
• Test all structural elements across clients

CSS Implementation Strategies

For CSS implementation, inline styles are preferable to external stylesheets, as many email clients strip out or ignore <style> tags in the email head. Additionally, specifying dimensions in pixels rather than percentages is recommended, as percentage values aren't consistently supported across email clients.

CSS approaches for enterprise email:

Inline CSS for critical styling:

<td style="font-family: Arial, sans-serif; font-size: 16px; color: #333333;">

Embedded CSS with client-specific hacks:

<style>

@media screen and (max-width: 480px) {

.mobile-full-width {

width: 100% !important;

max-width: 100% !important;

}

}

</style>

Image and Typography Considerations

Image suppression presents a significant challenge, as many email clients block images by default. To address this, always include descriptive alt-text for every image (something which can be handled by Knak AI). This approach ensures your message is conveyed even when images are disabled, improving accessibility for all users, including those using screen readers or voice assistants.

For enterprise teams concerned with brand consistency, alt-text becomes even more critical, as it may be the only brand element visible if images are blocked. Specifying image dimensions using HTML attributes also helps maintain layout when images are blocked.

For typography, select universally supported fonts to maintain consistent brand presentation:

• Arial/Helvetica
• Times New Roman/Times
• Georgia
• Verdana
• Tahoma

Testing Strategies for Enterprise Email Programs

For enterprise marketing operations, rigorous testing is essential given the scale and impact of email campaigns.

Comprehensive Testing Framework

Before sending any campaign, enterprise teams should implement systematic testing procedures that include:

1. Rendering tests across all major email clients and devices
2. Checking how emails appear with images disabled
3. Testing at different screen resolutions and display settings
4. Verifying that personalization renders correctly with different data inputs
5. Confirming that all links work properly and tracking is functioning

Rendering tests allow marketers to determine if adjustments need to be made to ensure emails display as intended across all recipient environments. For enterprise teams, automating these tests as much as possible is crucial to maintain efficiency while scaling quality assurance.

No-Code Solutions for Enterprise Email Rendering

The alternative for teams spending too much time and money on email creation is to invest in a platform that effectively manages rendering complexities. Many enterprise marketing platforms are built on top of responsive frameworks like MJML, a system that takes email code and renders it for every single mail client, across browsers and devices.

Benefits of No-Code Email Platforms

For enterprise teams, no-code platforms offer significant advantages:

• Brand consistency enforcement across all business units
• Reduced development time from days to hours
• Fewer rendering errors through standardized components
• Greater marketing agility by empowering non-technical users
• Centralized governance while maintaining local flexibility

When evaluating no-code solutions, look for:

• Rendering preview capabilities across multiple clients and devices
• Template systems that enforce rendering best practices
• Integration with other marketing systems
• Scale and performance capabilities for large subscriber bases

Future-Proofing Enterprise Email Rendering

Email continues to evolve, with new standards like AMP for Email and broader CSS support gradually being adopted. Enterprise marketing teams should stay current with these developments while maintaining reliable rendering across legacy clients.

Emerging Technologies and Standards

The email landscape is changing with innovations like:

• AMP for Email: Enabling interactive experiences within emails
• Dark Mode Support: Adapting to user preferences
• Improved Accessibility Standards: Making email more inclusive
• Enhanced Animation Support: Beyond basic GIFs
• Better CSS Support: As clients modernize their engines

Balancing Innovation with Reliability

For enterprise teams, the challenge is finding the right balance:

• Create a solid foundation that works across all clients
• Layer in progressive enhancements for modern clients
• Implement graceful fallbacks for older clients
• Test thoroughly across your audience's most common environments

Implementing an Enterprise Email Rendering Strategy

Email rendering is not just a technical challenge—it's an organizational one. Enterprise marketing operations teams need processes, skills, and governance to manage rendering at scale.

Building Email Rendering Expertise

Enterprise email marketing demands specialized knowledge that differs from web development. Organizations should consider:

• Dedicated email developers familiar with email-specific coding practices
• Design systems adapted for email's unique constraints
• Documented standards for email development across the organization
• Centralized quality assurance processes for consistent testing

Process Improvements for Better Rendering

Implement these process changes to improve rendering outcomes:

• Create a rendering requirements document for all email campaigns
• Establish client-specific design guidelines based on audience usage
• Develop modular, pre-tested components for common email elements
• Implement automated testing in your campaign workflow
• Maintain a rendering issue knowledge base for quick troubleshooting

Solving Enterprise Email Rendering Challenges Once And For All

Email rendering presents unique challenges for enterprise marketing operations teams managing large-scale email programs. The technical complexity, client diversity, and scale issues demand systematic approaches rather than ad hoc solutions.

A codeless campaign creation platform like Knak directly addresses these pain points by speeding up time-to-market by up to 95% while ensuring brand consistency across all communications. By eliminating the need for coding, Knak empowers non-technical marketers to create professional campaigns with its intuitive drag-and-drop editor while maintaining brand compliance through custom colors, fonts, and approved image libraries.

The platform's instant preview functionality allows teams to see how emails render on different devices and in different modes (including Dark Mode), significantly reducing rendering errors before deployment. With seamless integration across major marketing platforms like Marketo, Salesforce Marketing Cloud, and Eloqua, Knak enables enterprise teams to maintain rendering consistency at scale.

As email continues to evolve, staying current with rendering best practices becomes an ongoing operational requirement rather than a one-time project. For enterprise marketing operations, platforms like Knak build email rendering expertise into your workflow, ensuring consistent brand experiences regardless of how recipients view your messages, while allowing marketing teams to focus on creative strategy rather than technical implementation.

Ready to transform your enterprise email program? Book a demo to see how Knak can solve your rendering challenges while empowering your marketing team to create high-quality, brand-compliant emails in minutes rather than days