A/B testing (split testing) compares two versions of an email to learn what drives more opens, clicks, or replies. Learn how to run email A/B tests correctly and avoid common mistakes.
A/B testing (also called split testing) is the process of sending two variations of an email to similar audience samples to see which one performs better. In email marketing, this usually means testing one variable at a time such as the subject line, preview text, call-to-action, or send time.
A good A/B test uses a clear goal (opens, clicks, replies), a large enough sample, and a single change between version A and version B. Once you get a winner, you send that version to the remaining audience or apply the learning to future campaigns.
Common mistakes include changing multiple elements at once, judging results too quickly, or running tests on different segments where the audiences aren’t comparable. Keep tests focused, measure consistently, and document results so your email performance improves over time.