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A/B email testing

Learn what A/B testing is, how it works, the benefits it offers, best practices, and how to effectively A/B test your emails.

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Written by Support Team
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Overview

Email A/B testing (also known as split testing) allows you to send two different versions of an email to two random sample groups within your list. You can test subject lines or email designs to see which version performs better with your audience.

Note: HTML email is not supported for A/B tests.


Getting started

  1. Create a new message.

  2. Under Design Email, enable the A/B Testing toggle.

  3. Choose your test type: Subject Lines or Designs.

Testing email designs

Use this option to see which layout, images, buttons, or overall design drives more engagement (opens and clicks).

Steps:

  1. Design your email before enabling A/B Testing. This ensures Version A is duplicated as Version B, rather than starting from scratch.

  2. Select Designs, then click Create.

  3. Click Design Email to open the editor.

  4. Design Version A of your email.

  5. Switch to Version B using the drop-down and apply your changes.

  6. Click Save and Exit.

  7. Complete the Recipients, Sender, and Message details.

Notes:

  • When testing email designs, you can only use one subject line across both versions.

  • Once sent, the system automatically splits your selected email list into two random groups. Each half will receive either Version A or Version B.

  • If you turn off A/B testing, only Version A will be retained.


Testing subject lines

Use this option to find out which subject line leads to higher open rates.

Steps:

  1. Select Subject Lines as your test type.

  2. Enter both Subject Line A and Subject Line B.

  3. Click Save.

  4. Design your email as usual.

  5. Click Prepare to Send, then Send Now.

Note: If a subject line boosts open rates, consider updating the message preview for even better results. For tips on email marketing best practices, check out this helpful article.

Subject lines suggestions

Well-crafted subject lines can significantly increase open rates. Keep them short, relevant, and timely. Personalization and urgency (FOMO) can be effective.

Examples

  • Join us at Awesome Event, [Customer Name]

  • You’ll love to be here. Here’s your invite

  • We’re excited to announce [Event Name]

  • [Event Name] is in [X Days]. We’re pumped

  • Final day to get your VIP Tickets

  • The Awesome Music Festival is here. Details inside

  • Missed [Event]? SIGN UP for the next campaign

  • The countdown begins: X days to [Event Name]

  • Here’s your special invitation to [Event Name]

  • It’s official. [Celebrity] is coming to [Event Name]


A/B testing best practices

  • Define your goal: Know what you're testing (subject line, design, CTA) and why (e.g. increase engagement, improve conversions).

  • Focus on frequent sends: A/B testing is most useful for campaigns you send often (like newsletters or promos).

  • Wait 4–5 days: Give your test enough time to produce reliable results before analyzing. Results too early may be inconclusive.

  • Check for statistical significance: Only make changes based on meaningful results.

  • Repeat often: Customer behavior evolves. Re-test subject lines, designs, sender names, content, and timing regularly.


Viewing test results

Audience Republic makes it easy to see which A/B testing version performed best.

After your A/B email is sent, head to the Recipients tab to see which contacts received Version A and which received Version B.

For a detailed breakdown of key performance indicators (KPIs) for both versions, go to the A/B Test tab.

To view the content of each version, click View Message and use the toggle to switch between Version A and Version B.

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