This document provides an overview of mobile app testing challenges and best practices. It discusses the different types of mobile apps (native, mobile web, and hybrid), as well as challenges related to the large number of devices and OS versions, simulating real-life scenarios, usability, and development practices. Automation testing tools are presented, along with the importance of selecting representative devices for testing, simulating real-life scenarios, monitoring device logs, and using automation selectively on devices and simulators. The document concludes by offering ThoughtWorks' mobile app testing services.