A method used in marketing, product development, and UX/UI design to compare two versions of a webpage, app, cold email copy or other product against each other to determine which one performs better. This is done by randomly splitting the target audience into two groups: Group A, which experiences version A (the control), and Group B, which experiences version B (the variation). Key performance indicators (KPIs) such as click-through rates, conversion rates, and user engagement are measured to assess the effectiveness of each version. The primary goal of A/B testing is to make data-driven decisions that optimize user experience and maximize desired outcomes.