Jest is a delightful JavaScript Testing Framework with a focus on simplicity.

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

Voiden is a developer-first API client with local storage, Git-integrated, all based on markdown + offline support.

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.

Cloud-scale performance testing. Effortless load testing and synthetic checks at scale. Cloud-native and open-source. The next evolution of performance testing.

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