Performance

Load Testing

Validate API performance under load. Use k6 or Gatling to run smoke tests, load tests, stress tests, and capacity planning.

< 200ms

Response Time (P95)

< 500ms

Response Time (P99)

> 1000 RPS

Throughput

< 0.1%

Error Rate

> 99.9%

Availability

Load Test Profiles

Profile	VUs	Duration	Use Case
Smoke Test Minimal load to verify system works	1-5	1 min	CI/CD validation
Load Test Expected production traffic	50-200	10-30 min	Baseline performance
Stress Test Beyond normal capacity	200-1000	30-60 min	Find breaking points
Spike Test Sudden traffic bursts	10→1000→10	5-10 min	Elasticity testing
Soak Test Extended duration load	100-200	4-12 hours	Memory leaks, degradation

k6 Load Test Script

Modern load testing with JavaScript. Run locally or in the cloud.

loadtest.js

// k6 Load Test Script for JustKalm API
import http from 'k6/http';
import { check, sleep } from 'k6';
import { Rate, Trend } from 'k6/metrics';

// Custom metrics
const errorRate = new Rate('errors');
const valuationDuration = new Trend('valuation_duration');

// Test configuration
export const options = {
  stages: [
    { duration: '2m', target: 50 },   // Ramp up
    { duration: '5m', target: 100 },  // Steady state
    { duration: '2m', target: 200 },  // Stress
    { duration: '1m', target: 0 },    // Ramp down
  ],
  thresholds: {
    http_req_duration: ['p(95)<200', 'p(99)<500'],
    errors: ['rate<0.01'],
    valuation_duration: ['p(95)<300'],
  },
};

const API_BASE = 'https://api.justkalm.com';
const API_KEY = __ENV.JUSTKALM_API_KEY;

const products = [
  { brand: 'Louis Vuitton', category: 'bags', condition: 'excellent' },
  { brand: 'Rolex', category: 'watches', condition: 'good' },
  { brand: 'Hermès', category: 'bags', condition: 'new' },
  { brand: 'Cartier', category: 'jewelry', condition: 'excellent' },
];

export default function() {
  const product = products[Math.floor(Math.random() * products.length)];
  
  const startTime = Date.now();
  
  const response = http.post(
    `${API_BASE}/v1/valuations`,
    JSON.stringify(product),
    {
      headers: {
        'Authorization': `Bearer ${API_KEY}`,
        'Content-Type': 'application/json',
      },
    }
  );
  
  valuationDuration.add(Date.now() - startTime);
  
  const success = check(response, {
    'status is 200': (r) => r.status === 200,
    'has valuation id': (r) => JSON.parse(r.body).id !== undefined,
    'has estimated value': (r) => JSON.parse(r.body).estimated_value !== undefined,
  });
  
  errorRate.add(!success);
  
  sleep(Math.random() * 2 + 0.5); // 0.5-2.5s think time
}

# Run the load test
k6 run --env JUSTKALM_API_KEY=sk_test_... loadtest.js

# Run with cloud execution
k6 cloud loadtest.js

Best Practices

Run in CI/CD

Execute smoke tests on every deployment

Use Realistic Data

Feed tests with production-like payloads

Set Baselines

Establish performance baselines before changes

Monitor During Tests

Watch metrics in real-time for anomalies

Test from Multiple Regions

Validate latency from user locations

Schedule Regular Tests

Weekly soak tests catch regressions

Ready to Test Performance?

Get started with our test scripts and sandbox environment.

Open Sandbox