The Apache JMeter™ application is open source software, a 100% pure Java application designed to load test functional behavior and measure performance. It was originally designed for testing Web Applications but has since expanded to other test functions.

Anyone on your team can load test with instant playback, an easy-to-use interface, and real browsers for reliable data.

Locust is an open source performance/load testing tool for HTTP and other protocols. Its developer-friendly approach lets you define your tests in regular Python code. Locust tests can be run from command line or using its web-based UI

Robot Framework is a generic open source automation framework. It can be used for test automation and robotic process automation (RPA).

Orderly Ape is an open source (MIT) tool to run distributed and scalable k6 load tests on your own infrastructure using k6, kubernetes, grafana and influxdb.

Built for developers and testers alike, SoapUI is the only open source tool that covers the entire testing spectrum (functional, security, load, mocking).