A/B testing, also known as split testing, is a method of comparing two versions of a webpage, app, or marketing campaign to determine which one performs better. This is done by randomly showing one version to a group of users and the other version to another group, and then analyzing the data to see which version leads to higher engagement, conversions, or other desired outcomes. A/B testing allows businesses to make data-driven decisions and continuously improve their offerings, resulting in a more effective and successful overall strategy.