Non-functional testing is an important, but often ignored step in the process of developing applications. Gatling is a tool that enables us to simulate load, performs the associated measurement and presents the results of the performance testing. Why is Gatling detected by the ThoughtWorks radar? Because it is based on Akka, Netty and Scala technologies and so this lecture will show that writing performance scripts don’t have to be boring. With the concept and methodology of performance testing, using Gatling, the author will present personal experiences from previous projects testing the JVM applications.