load-testing

name	Load Testing
description	Performance testing under load. Use when: validating scalability, finding bottlenecks, or setting performance baselines.

Load Testing

Performance testing to validate system under load.

Tools

Tool	Use Case	Pros
k6	API/UI load	Scriptable, CI/CD friendly
Artillery	API testing	YAML config
Playwright	UI load	Real browser
ab (Apache Bench)	Quick smoke test	Simple

k6 Script

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

export const options = {
  stages: [
    { duration: '2m', target: 100 },  // Ramp up
    { duration: '5m', target: 100 },  // Stay at 100
    { duration: '2m', target: 0 },    // Ramp down
  ],
  thresholds: {
    http_req_duration: ['p(95)<500'],  // 95% under 500ms
    http_req_failed: ['rate<0.01'],      // <1% errors
  },
};

export default function () {
  const res = http.get('http://localhost:8080/api/messages');
  check(res, {
    'status is 200': (r) => r.status === 200,
    'response time < 500ms': (r) => r.timings.duration < 500,
  });
  sleep(1);
}

Running

# Install k6
npm install -g k6

# Run test
k6 run load-test.js

# With environment
k6 run -e TARGET_URL=https://api.mansoni.com load-test.js

Key Metrics

Metric	Good	Warning	Critical
p95 latency	< 200ms	200-500ms	> 500ms
Error rate	< 1%	1-5%	> 5%
Throughput	> 100 RPS	50-100 RPS	< 50 RPS

For Mansoni Chat API

// Chat load test
export const options = {
  scenarios: {
    chat: {
      executor: 'ramping-vus',
      startVUs: 0,
      stages: [
        { duration: '1m', target: 50 },
        { duration: '5m', target: 50 },
      ],
    },
  },
};

export default function () {
  // Send message
  http.post('http://localhost:8080/api/messages', JSON.stringify({
    content: `Load test message ${__VU}`,
    channel_id: 'test-channel',
  }), { headers: { 'Content-Type': 'application/json' } });

  // Fetch messages
  http.get('http://localhost:8080/api/messages?channel=test-channel');
}

Analyzing Results

     ✓ http_req_duration... avg=145ms p(95)=298ms
     ✓ http_req_failed... 0.5% (5/1000)
     ✓ iterations... 1000

Monitor for:

• Memory growth
• Connection pool exhaustion
• Error rate spikes
• Latency degradation