This document discusses how mobile app developers can use A/B testing and multivariate testing to optimize their apps. It provides examples of how testing different button text, media, and landing page elements led to significant increases in conversion rates for some companies. While the space is still developing, tools now exist to help app publishers test multiple variations without going through app store approval processes, providing localized tests, and gaining insights from rich analytics. The document encourages mobile developers to utilize testing to avoid leaving money on the table from suboptimal apps.