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.

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.

SeleniumBase Case Plans is Test Case Management Software that uses Markdown tables for displaying test plans directly in GitHub (and other source code management systems that support Markdown format).

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.

Free & OpenSource REST API Testing Tool for all levels in a Test Pyramid

Unifying API testing, API Performance testing, API Mocks and UI testing.