k6 — Modern Load Testing Tool Using Go and JavaScript

brew install k6                             # macOS
sudo apt install k6                         # Debian/Ubuntu
docker run --rm -i grafana/k6 run - < script.js

// load-test.js
import http from "k6/http";
import { check, sleep } from "k6";

export const options = {
  stages: [
    { duration: "30s", target: 50 },   // Ramp up to 50 VUs
    { duration: "1m",  target: 50 },   // Stay at 50
    { duration: "10s", target: 0 },    // Ramp down
  ],
  thresholds: {
    http_req_duration: ["p(95)<500"],   // 95th percentile < 500ms
    http_req_failed: ["rate<0.01"],     // Error rate < 1%
  },
};

export default function () {
  const res = http.get("https://api.tokrepo.com/assets");
  check(res, {
    "status is 200": (r) => r.status === 200,
    "body has assets": (r) => r.json().length > 0,
  });
  sleep(1);
}

k6 run load-test.js
k6 run --vus 100 --duration 2m load-test.js