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.

Loader.io is a free load testing service that allows you to stress test your web-apps & apis with thousands of concurrent connections.

Bruno is a Fast and Git-Friendly Opensource API client, aimed at revolutionizing the status quo represented by Postman, Insomnia and similar tools out there.

Hoppscotch is an open-source API development ecosystem that helps you create and test your API requests saving precious time in development.

Free and open source. Solve accessibility issues before they reach your customers.

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