k6

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k6 is a modern load-testing tool, built on our years of experience in the performance and testing industries. It's built to be powerful, extensible, and full-featured. The key design goal is to provide the best developer experience.

Its core features are:

Configurable load generation. Even lower-end machines can simulate lots of traffic.
Tests as code. Reuse scripts, modularize logic, version control, and integrate tests with your CI.
A full-featured API. The scripting API is packed with features that help you simulate real application traffic.
An embedded JavaScript engine. The performance of Go, the scripting familiarity of JavaScript.
Multiple Protocol support. HTTP, WebSockets, gRPC, Browser, and more.
Large extension ecosystem. You can extend k6 to support your needs. And many people have already shared their extensions with the community! Explore the available extensions.
Flexible metrics storage and visualization. Summary statistics or granular metrics, exported to the service of your choice.
Native integration with Grafana cloud. SaaS solution for test execution, metrics correlation, data analysis, and more.

This is what load testing looks like in the 21st century.

Example script

    import http from "k6/http";
    import { check, sleep } from "k6";

    // Test configuration
    export const options = {
      thresholds: {
        // Assert that 99% of requests finish within 3000ms.
        http_req_duration: ["p(99) < 3000"],
      },
      // Ramp the number of virtual users up and down
      stages: [
        { duration: "30s", target: 15 },
        { duration: "1m", target: 15 },
        { duration: "20s", target: 0 },
      ],
    };

    // Simulated user behavior
    export default function () {
      let res = http.get("https://quickpizza.grafana.com");
      // Validate response status
      check(res, { "status was 200": (r) => r.status == 200 });
      sleep(1);
    }

You can run scripts like this on the CLI, or in your CI, or across a Kubernetes cluster.

Tags: tool testing load testing ecmascript

Last modified 11 September 2026

k6

A modern load testing tool, using Go and JavaScript.

Example script