Introduction

A/B testing is vital to any email marketing strategy, allowing you to test different subject lines, layouts, and copy to see what resonates best with your audience. In Marketo, this process is no different, but when it comes to custom email templates, the design integrity of your emails is just as important as the test itself. A simple mistake during testing can break your carefully crafted design, causing it to appear distorted in recipients’ inboxes.

This article aims to guide you through A/B testing in Marketo while keeping your email design intact. Whether you’re testing subject lines, CTAs, or content layout, the goal is to ensure that your testing doesn’t interfere with your brand’s visual identity, ensuring that each version looks just as good across devices and email clients. Let’s explore how to execute effective A/B testing in Marketo without compromising your email template’s design.

Start by Understanding What You Can and Can’t Test in Marketo

Before diving into the process of A/B testing, it’s essential to understand the boundaries of Marketo’s native testing functionality. Marketo supports several types of A/B tests, including subject line tests, testing of different “From” names, send-time optimization, and testing entire email variations. However, it is crucial to know that some elements, especially those embedded within custom HTML email templates, may not be easily testable.

For instance, testing layout changes within a custom HTML template can be challenging because Marketo does not allow for the dynamic adjustment of intricate design elements within individual test variants. This makes it essential to understand which elements are customizable in Marketo HTML email templates and which ones may cause layout issues when switched out for testing purposes. Recognizing these limitations can help avoid frustration later on and ensure you don’t accidentally disrupt the structure of your email.

Keep Your HTML Email Template Modular from the Start

One of the most important design principles when preparing for A/B testing in Marketo is ensuring your email template is modular. Modular design refers to breaking down the email template into smaller, reusable sections or blocks, such as text areas, images, buttons, and headers. This practice allows you to easily swap out components for testing without affecting the overall layout of the email.

In Marketo, you can create modular email templates by utilizing editable components like mktoText, mktoImg, and mktoButton. By segmenting your design into clearly defined blocks, you can easily test different versions of these blocks without impacting the rest of the email. For example, testing two versions of a CTA button or a new header layout can be done without altering the rest of the email content. Consistent naming conventions and clear segmentation also make it easier to maintain the structure during testing.

Test Only One Thing at a Time — Seriously

While it can be tempting to test multiple design elements in one go, this can lead to unintended consequences. It’s essential to stick to the principle of testing only one variable at a time. This is especially true when dealing with complex custom HTML email templates, where even small changes can affect how the email is rendered across different devices and email clients.

For instance, if you want to test a new CTA button, it’s crucial to focus solely on that element rather than changing multiple design components in one test. Changing the color, copy, and placement of the button all at once may result in conflicting data and make it harder to interpret what’s actually driving the results. Keeping your test simple—like testing two different CTA button designs with the same email content—ensures that your results are more reliable and actionable.

Use Preview Tools Before Hitting Send

Testing your A/B versions is only useful if the email renders as intended across different platforms. Marketo provides preview tools that allow you to see what your email will look like across different devices and clients before you send it. Utilizing these tools ensures that you spot any issues before hitting send and ensures that both A and B versions look exactly the same.

In addition to Marketo’s built-in preview functionality, consider using external email testing platforms like Litmus or Email on Acid. These platforms offer enhanced email rendering previews for various email clients, helping to ensure that your email will look perfect whether it’s viewed on Outlook, Gmail, or mobile devices. By using preview tools, you can catch any layout issues before they impact your results, saving you from design headaches later on.

Be Smart About Segmenting Your Audience for A/B Tests

An often overlooked but crucial element in A/B testing is audience segmentation. Even the most well-designed email can underperform if it reaches the wrong audience. Marketo allows you to segment your list for A/B testing, ensuring that each test variation reaches a similar, random subset of your audience. This randomization ensures that external factors, such as recipient demographics or behavior, don’t skew your test results.

The key to successful segmentation is ensuring that both your A and B test groups are of equal size and match in composition. If one test group is much larger or more engaged than the other, your results could be misleading. Marketo’s built-in A/B testing feature takes care of much of this for you, but it’s essential to double-check your settings and ensure your segments are correctly set up. Proper audience segmentation allows you to gather reliable, actionable insights from your test results.

Don’t Skip the Post-Test Cleanup and Version Control

Once your test is complete and you’ve identified the winning version, it’s important to properly clean up your Marketo account. Document your findings and archive both the A and B versions of the email for future reference. This version control helps ensure that you can reuse the winning version in subsequent campaigns without needing to redo the design or test.

Additionally, it’s crucial to remove any outdated or unnecessary code from your template after the test. Leftover code or unused variables can clutter your template, which could result in broken designs or performance issues in future campaigns. Keeping your templates organized and free of unnecessary code is an often-overlooked but essential practice for maintaining consistent email quality.

Conclusion

Setting up A/B testing in Marketo doesn’t have to result in design disasters. By following best practices like using modular email templates, focusing on one variable at a time, leveraging preview tools, and segmenting your audience properly, you can ensure your emails not only perform better but also maintain their visual integrity across all devices. Remember that A/B testing is an ongoing process, so keep refining your approach based on your results.

By being thoughtful about how you set up your tests and managing the design with care, you’ll be able to drive better engagement and conversion rates while preserving your brand’s look and feel. Marketo is a powerful tool, and with the right strategy, it can help you create more effective, visually appealing email campaigns that resonate with your audience.