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.

Similar Tools

k6 Open Source is designed for load testing. Extensible to support other types of testing.
An open source JS tool for image analysis and comparison. A successor of PhantomCSS.
Comprehensive and user-friendly cloud platform for Load Testing, Speed Testing and Website & API Optimization and Monitoring
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).
YATTIE exists to help make tester's lives easier. Ideally, it should remove friction from the exploratory testing process - everywhere from gathering evidence to submitting reports.
Performance testing with Flood increases customer satisfaction and confidence in your production apps and reduces business risk.