Load testing completed simulating at least 2x expected peak traffic; application stable with error rate under 1%

Deploying to production without load testing means your application's failure threshold under traffic is unknown until it collapses. ISO 25010 performance-efficiency.capacity requires knowing the system's limits before they are breached. NIST SC-5 covers resource availability protection. A deployment that handles 50 concurrent users gracefully may fail at 200 — a traffic spike from a product launch, press mention, or marketing campaign will find that limit in the worst possible context. A 2x peak traffic load test with under 1% error rate gives you a defensible headroom margin.

Run a load test using k6. Install it and create a test script that ramps to 2x expected peak traffic.

npm install --save-dev k6

// load-test.js
import http from 'k6/http';
import { check } from 'k6';

export const options = {
  stages: [
    { duration: '2m', target: 100 },   // ramp up to expected peak
    { duration: '5m', target: 200 },   // hold at 2x peak
    { duration: '2m', target: 0 },     // ramp down
  ],
  thresholds: {
    http_req_failed: ['rate<0.01'],    // <1% errors
    http_req_duration: ['p(95)<500'],  // 95th percentile under 500ms
  },
};

export default function () {
  const res = http.get('https://your-app.com/');
  check(res, { 'status is 200': (r) => r.status === 200 });
}

Run with k6 run load-test.js and document results (p50, p95, error rate, peak concurrent users) in DEPLOYMENT.md.