Mass email campaigns are a staple of digital marketing, providing a powerful way to reach a large audience quickly. However, ensuring that your email content resonates with your audience can be challenging. One of the most effective ways to optimise email performance is through A/B testing, a feature that has been core functionality for a long time and is now fully implemented using Mosaico.

Improved Open Rates

A/B testing can reveal which subject lines or sender names attract the most attention. By testing different options on a subset of your email list, you can determine which version yields the highest open rates. For example, a more personalised subject line may increase the likelihood of an open, while an overly ‘support us’ oriented one might not perform as well. With A/B testing, you gain a clear picture of what your audience prefers.

Click-Through Rates and Content Relevance

Once a recipient opens your email, the next goal is engagement—typically measured by click-through rate (CTR). Testing variations in calls-to-action (CTAs), email design, or the placement of links can reveal what drives engagement. A/B testing allows you to identify small changes that lead to big improvements, helping you understand which version is most likely to encourage clicks.

A/B testing helps uncover what type of content is most relevant to your audience. By experimenting with different text, images, or appeals, you can identify what resonates most. A/B testing can show you which aspect of your message has the greatest appeal, leading to higher engagement and conversion rates.

Increased Conversion Rates

Optimising for open and click-through rates can lead to more conversions, but A/B testing also allows you to test the final step in your funnel. Whether you’re looking to increase membership sign-ups, donations or event registrations, testing different elements — such as the landing page layout linked in your email or a specific contribution page — can help you find the most effective approach to turn engagement into action.

Informed Decision-Making with Data

Instead of relying on guesswork, A/B testing provides concrete data on what works best for your audience. This data-driven approach not only improves current campaigns but also guides future strategies. Over time, A/B testing reveals patterns, enabling you to make informed decisions and create even more effective communication strategies.

Running A/B tests for mass email campaigns empowers you  to optimise content, increase engagement, and ultimately boost conversions. With A/B testing, each campaign becomes an opportunity to learn more about your audience and refine your messaging, leading to stronger performance and a more effective email strategy overall.

Support and further info

Adding A/B testing for email design was introduced earlier this year in Mosaico 3.5 and adding different ‘from’ email addresses in Mosaico 3.6 which was released in September 2024.

If  you need help getting started or get stuck, please feel free to get in touch by posting on CiviCRM StackExchange or use the user support channel in chat.

Acknowledgments

We benefit a lot from Civi and are always looking for ways to contribute back. This was a feature that was requested by our clients. We knew it had the potential to be beneficial to others, so we made the effort to work with the core team and our clients to make it happen. 

We’d like to take a moment to thank those clients, whose funding made these improvements possible and the Core Team for their work and support in getting these features across the finish line.