A/B testing in email marketing is a method of comparing two versions of an email to determine which one performs better in terms of open rates, click-through rates, and conversions. This involves sending out two variations of the same email to a small sample of subscribers and analyzing the results to determine which version is more effective. By conducting A/B testing, email marketers can gain valuable insights into their audience’s preferences and behaviors, allowing them to optimize their email campaigns for maximum impact and success.