Split testing (also known as A/B testing) is a way to compare two or more versions of an email, webpage, or ad to see which one works better. In email marketing, this means sending different versions of an email to parts of your audience and checking which gets more opens, clicks, or responses.

Split testing can help you:

  • Find what works best: Not every message connects the same way with your audience. Split testing helps you see what gets attention and encourages action.
  • Increase email engagement: Trying different subject lines, content, or layouts can show you which version gets more people to open and click.
  • Improve results over time: Testing and adjusting helps you learn what leads to more sign-ups, sales, or replies.
  • Make informed choices: Instead of guessing, you can use real numbers to decide what works best for future emails.

How to split test an email or SMS message

Step 1: Create a message with more than one version

Before sending a message to your full audience, you can test different versions to see which one performs better.

  1. Go to Marketing > Emails & SMS.
  2. Click + Email/SMS in the top right corner.
  3. Choose Email or SMS and name your message.
  4. Click Create.
  5. In the new message settings, click + New Version in the "Design and configure" section.

This creates a second version of the message for testing. You can create more versions if needed.

Create versions for emails

Step 2: Configure the split test

By controlling how many people receive each version, you can compare their performance and see which are most effective. This helps you know how to improve future messages.

  1. Click the three dots next to Version B.
  2. Enter the percentage of people you want to receive Version B.
  3. Version A will automatically get the rest.
    Define percentage for each split email version
Tip: If you want to test more than one alternate version, click + New Version again to add Version C, Version D, etc. You simply need to ensure that all versions combined add up to 100%.

Step 3: Write your message versions

Testing different subject lines, images, or buttons can help you find what works best.

  1. Click between Version A, Version B, etc. to select the version you want to edit.
  2. Click Edit message to open the editor.
  3. Adjust your text, images, links, or buttons.

Pro tip

Change just one thing per test—such as the call-to-action button text (e.g., "Sign up now" vs. "Get your download"). If you change too many things at once, you won’t know which change made the difference.

Step 4: Test each version before sending

Before sending your message to your full list, test each version to ensure it looks and works as expected. You have two ways to test:

  • Send a test email: Quickly check formatting, links, and overall appearance.
  • Send a live test: Use a small test group to review how variables (like names) display and how automations function.

Choose the method that best fits your needs, or use both for a thorough review.

Option 1: Send a test email

In the email settings:

  1. Click between Version A, Version B, etc., to select a version. 
  2. Click Edit Message to open the editor, then Send test email.
    Send a test email
  3. Enter your own email address and send the test. 
  4. Go to your email inbox to check how the message looks on desktop and mobile.
Important: Test emails are sent from [email protected]. The final email will be sent from your configured gateway. Placeholder variables (like {first_name}) appear as "TEST" in test mode but will populate correctly in real messages.

Option 2: Send live to a small test list

  1. Go to Contacts > Lists and create a test list with coworkers, team members, or yourself. Learn more about Lists.
  2. Navigate back to the email draft with your split test versions and open the settings.
  3. In the From-To tab, filter communication recipients to send only to those subscribed to the test list.
  4. Send the message and check:
    • How each version looks in inboxes. Each recipient will receive only one of the versions added for split testing–A, B, etc.
    • If all links and buttons work for each version.
    • Feedback from your test group.
  5. Review Email & SMS analytics in Kartra to see how opens and clicks are tracked for each version.

Step 5: Send your tested message to your audience

Once testing is complete, clone the split-tested email to send it to your entire list.

  1. Clone the tested message (broadcasts can't be resent once sent).
  2. Make any last adjustments based on feedback and test results.
  3. Click Send / Schedule to send the message.

Understanding the analytics

To check how your split test performed, go to Marketing > Emails & SMS and find your broadcast in the dashboard. Hover over the icons to see a quick summary of the results:

Split Test Analytics

  • Recipients: Total number of people who received the message.
  • Version distribution: Percentage of recipients who got each version.
  • Open rate: Percentage of recipients who opened each version of the email.
  • Click rate: Percentage of recipients who clicked a link in each version.

For a more detailed breakdown, go to Marketing > Emails & SMS > Analytics.

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