It’s a technique for comparing the outcomes of two separate emails and drawing conclusions from them. As the name implies, you create two or more email versions and label them A, B, C, and so on. You put it to the test on different people and compare the results to determine which one has the most sway. 

A/B testing is a marketing model that tests the efficacy of two different versions of a website, ad, email, popup, or landing page. It’s one of the most efficient strategies to boost conversions.