Mobile A/B testing is a method of testing two versions of a mobile app or website to determine which one performs better in terms of user engagement and conversion rates. This process involves randomly dividing users into two groups and showing each group a different version of the app or website. By analyzing the data and user behavior, developers can make informed decisions on which version to implement permanently. This allows for continuous improvement and optimization of the mobile experience, ultimately leading to a more successful and user-friendly product.