An A/B test (also known as an A/B/n test or A/B experiment) is a randomized experiment using 2 or more variants on the same web page. Variant A is the original version of the web page. Variants B through n each contain at least one element that differs from the original version. Each variant is shown to a random sample of users at the same time.
The purpose of the test is to determine which version performs better at achieving a specific goal. For example, you might look at which variant increases click-through rates, conversion rates, or engagement rates.