A/B tests, also known as split testing, are crucial for optimizing email marketing strategies. Two variants of a campaign are compared to analyze audience response. From landing page design to subject lines and calls to action, these tests are essential for improving metrics and understanding audience preferences.

Definition of A/B Testing

We need to define the term before moving on to best practices for A/B testing. Comparing your audience's responses to two variations of an email or campaign is called A/B testing, sometimes referred to as split testing.

This pair of versions should differ in a crucial aspect. While it's not necessary for the audience to distinguish between the two versions, marketing professionals should.

For example, if you want to determine which email marketing templates are more effective for your company, make sure to select a fully adjustable design that allows you to define two variables. Then, send two test campaigns, one for each variable, and evaluate the results.

You can produce email marketing campaigns, websites, landing page content, and other marketing materials that resonate and evoke an emotional response from your audience using this scientific technique.

In general, A/B testing is one of the most cost-effective methods to find out what your target audience prefers from your brand and all your marketing initiatives.

"Testing your website or app with users is the best way to create a good user experience." Similarly, your email marketing campaigns should focus on producing content that informs, educates, and strengthens the relationship between your company and the consumer.

What Type of A/B Test Should You Do in Email Marketing?

Testing the right thing at the right time is essential because email marketing is undoubtedly one of the most cost-effective strategies to promote your marketing message. Here's why:

The impressive return on investment indicates that sending untested or unoptimized emails is like leaving money on the table. However, what elements should you test to improve your metrics?

Your Lead Generation Efforts

If you want to build an email list, you need to generate leads that will turn into subscribers who will then agree to receive your email marketing messages. For this, you'll need a tool that helps you develop, test, and refine your lead generation assets, such as landing pages and subscription forms.

A/B Testing of the Landing Page

Let's start with your design work. A lead will notice your landing page design immediately. Examine the design, tones, and links on your landing page.

Next, make sure to check colors, typography, and other aspects like main images and customer testimonials. Are they comprehensive enough? Do they hold up well? Does the design match the message? How do the colors look?

Answers to these questions will come from A/B testing.

Don't forget to add your Unique Selling Proposition (USP) to your content. Determine which of your two USP variations better answers the customer's main question: "Why should I use your product over the competition's?".

You don't need lengthy content, since your landing page is not the right place for selling. In case the results of your A/B tests indicate that you need more engaging long-form content, keep it concise and sweet and incorporate customer endorsements.

Lastly, pay attention to your CTA (Call To Action) button. Use actionable verbs that can guide the user from point A to point B and choose colors that complement your brand tone and the purpose of the landing page.

A/B Testing of Your Subscription Forms

While this may be sufficient in many situations, not all organizations can benefit from asking only for the name and email address of a potential customer. To effectively segment and distribute different marketing messages to different functions within the same company, B2B companies need additional data.

Firstly, choose how many fields your form can have. Lengthy forms can lead to increased exclusion rates, and pop-ups can annoy your viewers. You can determine your audience's preferences and focus your efforts more effectively by A/B testing the form and its placement.

Another crucial component of your lead generation efforts is the form design. While GIFs may be visually appealing to some viewers, others may prefer to see a sample of what should be entered in each form field.

Assuming your lead generation A/B test is impeccable. Now let's talk about email marketing campaigns.

Your Email Marketing Messages

If you don't have enough leads, email marketing can be a costly marketing strategy to avoid. The same goes for email marketing initiatives that are distributed to a significant portion of your audience without undergoing A/B testing.

When it comes to improving your stats and achieving higher open and click-through rates, the subject line is as crucial as the sender's address. You can improve these KPIs with A/B testing in a way that makes sense for your business and is based on facts.

  • Your Subject Line

    Starting with what creates the first impression of your brand, the email subject line is there to convince the user to open your email. This means, as a marketer, you need to be sure of how you can use the "free space" of the subject line. Here's what I mean:

    Although the ideal length is 41 to 50 characters, a subject line of 60 characters may be well-received by the audience.

    A clever sales subject line (up to 40 characters) might work wonders for a sales campaign, but what about a newsletter? Create two versions of the same and investigate the following:

    • Is the phrase too cryptic, too salesy, or just right?
    • Does your brand tone match your marketing message?
    • Could it be longer or shorter? How does it look in different email clients and hardware?
    • What level of personalization is appropriate for my subject line?
    • Is my audience unfamiliar with using emojis or uninterested in them, or do I really need to use them?
    • Am I using meaningful words?
    • Am I guiding the user in the right direction?

    A well-crafted subject line can make the difference between an email getting delivered or not getting opened, or both.

    Also, use the terms you have at your disposal. Avoid using symbols like "$$" or terms like "Free" as they can trigger spam filters.

  • Your Campaign Content

    The wording and content of your campaign will be what keeps user engagement and drives your click-through rates to new heights. At this point, it's time to answer more questions:

    • Should I use short or long text for my campaign?
    • How many images can I use in this message?
    • Are images enough as visual aids, or would a testimonial video work better? Think about GIFs. Maybe they're necessary too?
    • Is the typography suitable for my brand tone and marketing message? Is it too exaggerated or too subtle?
    • Are the colors appropriate and sufficient?
    • What should I use: buttons, naked links, or both?

    Your material may be too long or too short for your target audience, even if it seems perfect for your campaign. Additionally, your brand tone may prohibit shorter or longer copies. To check this, you need to perform A/B tests and experiment with longer and shorter versions, as well as more formal or informal content.

    And when we talk about material, we also include the images. Check how your audience responds to impactful images or GIFs. Your recipients may disagree with your choice or prefer an infographic over a banner image.

  • Your Call to Action (CTA)

    Whether it's an offer or simple information, the Call To Action (CTA) button indicates the steps users need to take to receive what the email promises.

    What action do you require your users to take now? This is the moment to communicate your viewpoint clearly. Consider the following:

    • How would I more effectively convert my CTA? Should I use two buttons or just one?
    • How do I express it? Do I need my button to have more than a few words, or can it be as simple as an actionable verb?
    • What tone would be most effective? Red is an activity color, but does it fit my brand tone?

    The CTA will indicate to consumers how to proceed and provide them with the benefits of following your recommendation. Therefore, it is imperative to use all tools at your disposal, including sophisticated wordplay, puns, and color psychology.

    When it comes to your CTA button, using contrasting colors is a great idea. They can bring it to life and capture attention. However, that doesn't mean your audience will find it pleasing. This also applies to the size of your CTA button. All devices used by recipients should be able to click on it, but what precise size piques their interest enough to provoke a click? The same goes for the button's placement. Some people prefer to be shown the right path, while others would like to know what to do right away.

More A/B Testing Tips for Email Marketing

You will have a competitive advantage if you use A/B testing for email marketing in particular, but there are some best practices that are universally applicable.

If you're unsure what to do, A/B testing can be a challenging procedure. Let's now look at tips that shouldn't be overlooked in your plan.

  • Never Test More Than One Variant Simultaneously

    Although testing more than one variant is feasible, A/B tests are not designed this way. Because you only need to test one hypothesis - rather than all variants that may matter - and set up the A and B groups. Then, go into broadcast mode.

    Always test one variant at a time. You won't be able to tell which of the two variations of your email marketing campaign - the one with an almost identical CTA and a slightly different subject line - was more effective with your audience. As a result, you won't be able to decide which version is ideal for your Conversion Rate Optimization (CRO) initiatives.

  • First, Test with Your Audience

    Knowing what element to modify indicates that you thoroughly understand your target audience. And in the end, this is what will matter. Remember that you are testing your brand in relation to your audience, not your brand itself.

    This implies that you need to understand the factors that, in your case, would be statistically significant and would eventually lead to change.

    Of course, it's necessary to test for all metrics and stages of the funnel to ensure a result you can trust. Although important, the CTR (click-through rate) is not everything.

    Understanding your target audience and the funnel stages you are testing for will help you produce content that will provide you with reliable results. For example, it's not really the best idea to use UGC in an email marketing campaign that repeaters are A/B testing.

    Additionally, to make informed, data-driven decisions, you need to consider factors other than demographics.

  • Conduct Multiple Tests Simultaneously

    You can't afford to waste time testing variant X one week and variant Y the next, as you're testing two versions of the same marketing message.

    This is because your data will lose validity over time due to the time period in which you obtained it may influence it.

    Running tests simultaneously eliminates the possibility of time working against you.

    Of course, you should never test with audiences that are not identical or similar to ensure that no factor will influence your data and that you can draw correct conclusions. Regardless of the version you decided to modify, you should test with the "mother" demographic if you're selling maternity wear.

    This way, you can determine whether adding a red CTA button or an emoji to your subject line significantly increases the open rate and boosts sales conversion.

  • Nothing Is Too Small to Test

    Nothing is too small or too random to test when it comes to successful A/B testing. Naturally, everyone will immediately think of the CTA button and subscription form fields, but there are other equally crucial elements that you'll need to test later.

    You can gather more information about your customers' spending habits by testing alternative promotions, different delivery times, and distinct target audiences. You can also discover what works and what is out of season for your audience. Ultimately, the success of an email marketing campaign will depend on these factors.

    At this point, you could enhance your data and make informed decisions by combining the power of an A/B email testing campaign with a questionnaire.


A/B testing is a valuable tool in the email marketing arsenal. From lead generation to designing landing pages and campaign content, these tests offer crucial insights. Remembering the importance of individualized testing, thoroughly understanding the audience, and testing multiple elements simultaneously ensures solid results. Ultimately, combining the strength of A/B testing with additional data, such as surveys, drives the success of email marketing campaigns.


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