What's new

Optimize SMS performance and A/B test content in flows

Anthony DelPizzo, January 12th 2023

In this product release

A/B testing is a pivotal tactic for marketers to make data-driven decisions, allowing you to test different options of content, design, and more. At Klaviyo, we aim to provide you with the tools to experiment with your marketing to continuously optimize and discover what works best for you and your customers, and A/B testing is a foundational feature of ours. You can find this functionality across email and SMS, and as of today, we’re excited to announce that A/B testing is now available in SMS flows, allowing you to maximize performance in your text automations. 

The challenge

No efficient way to test SMS content at scale

Text message marketing is becoming increasingly popular — over one in three consumers prefer to communicate with their favorite brands via text over email, and more than twice as many shoppers would rather hear from you via text message than over social media. But while consumers prefer to text with their favorite brands, studies show that they’re only willing to subscribe to a handful of brands via SMS —meaning your messages have to be extra relevant to get on that short-list. 

To ensure you’re providing value to your customers over text, it’s important to use the right tone, copy, and imagery that they’ll engage with most. But how does one know what will work best, might you ask? Rather than guessing, you can test different messages and try different forms of content to see what performs best. In some tools, that might mean creating separate campaigns or automations with different text variations, which means you’ll have to pull results separately, spend hours comparing different metrics for each variation, and then hopefully come to the conclusion on your own. It can be quite time consuming.

The solution

A/B test different content variations within the same flow 

In Klaviyo, we make testing different variations of SMS messages at scale a breeze. From right within the same flow, you can easily set up an A/B test for any of your SMS automations — allowing you to automatically find the version of your content that performs better — maximizing performance, efficiency, and visibility. That means you can test copy, emojis, images (MMS only available in select regions), and more to determine exactly what resonates most with your audience. 

The best part? Klaviyo’s A/B testing does the work for you — automatically selecting test winners once statistical significance is reached (or a selected end date of your choice) — meaning you can set it, forget it, and trust that the winning text will be sent to the rest of your audience. Plus, you can easily see the status of your test at any time by clicking on the flow — providing you with quick visibility into the high-level results and the ability to click right into the granular details, if you’d like. 

Some best practices to keep in mind when A/B testing SMS:

  • Test 1 aspect at a time
  • Include a link and use the Klaviyo link shortener
  • Test different types of SMS flow messages (e.g. abandoned cart and welcome messages)
  • Keep any images or GIFs under 600 KB

Getting started

Setting up an A/B test for SMS messages in flows couldn’t be easier. It’s the same A/B testing process throughout Klaviyo that you already know and love — head to any flow with SMS, click on the message itself, and click ‘create A/B test’ to begin crafting the two content variations to test. 


Head to your flows tab today to begin making more data-driven decisions in your SMS automations. More data to power decisions the better, right? We think so. If you’d like to learn more about SMS A/B testing, check out our help center.