Load testing software is an evaluation tool for determining how an application will perform as the work level approaches the limits of the application's specifications.
The primary goal of load testing is to define the maximum amount of work a system can handle without performance slipping significantly. The process of increasing the load beyond its known capacity and seeing how that load affects the application is sometimes called stress testing.
Load testing and stress testing both fall under the umbrella term application performance management. Also known as application performance monitoring, APM is about finding the root causes of poor performance and fixing issues related to user interfaces, network, databases and application code.