Mobile applications and mobile websites have become a major channel for conducting business, improving employee efficiency, communicating, and reaching consumers. In the past, mobile played a smaller role in business applications, so performance issues and outages were less of a concern. This is no longer the case. Today, performance problems with mobile applications lead directly to revenue loss, brand damage, and diminished employee productivity. Part I of this article discusses the differences between testing traditional web and mobile applications, specific challenges associated with mobile load testing, mobile testing basics and best practices for recording mobile load test scenarios. In Part II, we will look at how to conduct realistic tests and how to best analyze the results.