k6

k6 is an open-source load testing tool from Grafana Labs, built around scripting test scenarios in JavaScript rather than clicking through a GUI recorder. A developer writes virtual-user behavior as code - which requests to send, how many users to simulate, how load should ramp up over time - and k6 runs that script from the command line, making it straightforward to check into version control and run the same way locally and in CI.

It integrates naturally with CI/CD pipelines to run performance checks on every build, and its output feeds into Grafana dashboards (also in this catalog) for visualizing throughput, latency, and error rates over the course of a test run.

k6 is a fit for teams that want load and performance testing to be as easy to write, review, and automate as their existing unit and integration tests, complementing Cypress and Playwright (also in this catalog), which test correctness and user flows rather than performance under load.