Locust is an innovative open-source load testing tool designed to assess and measure the performance of web applications under stress. Originating in Python, it allows users to simulate millions of concurrent users interacting with their systems in order to identify bottlenecks and optimize infrastructure. Known for its user-friendly interface and scalability, Locust enables developers and testers to create complex testing scenarios using lightweight scripts. Its flexibility and the ability to distribute tests across multiple machines have made it a popular choice for performance engineers and IT professionals globally.