Gatling is a powerful open-source load testing solution that integrates with your development pipeline. It includes a web recorder and colorful reports.

The Complete Continuous Testing Platform Any test. Any device. App quality without limits.

k6 Open Source is designed for load testing. Extensible to support other types of testing.

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).

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