
About
Comprehensive k6 load testing skill for API, browser, and scalability testing. Write realistic load scenarios, analyze results, and integrate with CI/CD.
name: k6-load-testing description: "Comprehensive k6 load testing skill for API, browser, and scalability testing. Write realistic load scenarios, analyze results, and integrate with CI/CD." category: testing risk: safe source: community date_added: "2026-03-13" author: Kairo Official tags: [k6, load-testing, performance, api-testing, ci-cd] tools: [claude, cursor, gemini]
k6 Load Testing
Overview
k6 is a modern, developer-centric load testing tool that helps you write and execute performance tests for HTTP APIs, WebSocket endpoints, and browser scenarios. This skill provides comprehensive guidance on writing realistic load tests, configuring test scenarios (smoke, load, stress, spike, soak), analyzing results, and integrating with CI/CD pipelines.
Use this skill when you need to validate system performance, identify bottlenecks, ensure SLA compliance, or catch performance regressions before deployment.
When to Use This Skill
- Use when you need to load test HTTP APIs, WebSocket endpoints, or browser scenarios
- Use when setting up performance regression tests in CI/CD
- Use when analyzing system behavior under various load conditions
- Use when comparing performance between code changes
- Use when validating SLA requirements and performance budgets
k6 Basics
Installation
# macOS
brew install k6
# Windows
choco install k6
# Linux
sudo gpg -k
sudo gpg --no-default-keyring --keyring /usr/share/keyrings/k6-archive-keyring.gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys C5AD17C747E3415A3642D57D77C6C491D6AC1D69
echo "deb [signed-by=/usr/share/keyrings/k6-archive-keyring.gpg] https://dl.k6.io/deb stable main" | sudo tee /etc/apt/sources.list.d/k6.list
sudo apt-get update
sudo apt-get install k6
Quick Start
// simple-test.js
import http from 'k6/http';
import { check, sleep } from 'k6';
export const options = {
vus: 10,
duration: '30s',
};
export default function () {
const res = http.get('https://httpbin.test.k6.io/get');
check(res, {
'status is 200': (r) => r.status === 200,
'response time < 500ms': (r) => r.timings.duration < 500,
});
sleep(1);
}
Run with: k6 run simple-test.js
Test Configuration
Common Options
export const options = {
// Virtual Users (concurrent users)
vus: 100,
// Test duration
duration: '5m',
// Or use stages for ramp-up/ramp-down
stages: [
{ duration: '30s', target: 20 }, // Ramp up
{ duration: '1m', target: 100 }, // Stay at 100
{ duration: '30s', target: 0 }, // Ramp down
],
// Thresholds (SLA)
thresholds: {
http_req_duration: ['p(95)<500'], // 95% requests < 500ms
http_req_failed: ['rate<0.01'], // Error rate < 1%
},
// Load zones (distributed testing)
ext: {
loadimpact: {
name: 'My Load Test',
distribution: {
'amazon:us:ashburn': { weight: 50 },
'amazon:eu: Dublin': { weight: 50 },
},
},
},
};
Test Types
| Type | Use Case | Configuration | |------|----------|---------------| | Smoke Test | Verify basic functionality | Low VUs (1-5), short duration | | Load Test | Normal expected load | Target VUs based on traffic | | Stress Test | Find breaking point | Ramp beyond capacity | | Spike Test | Sudden traffic spikes | Rapid increase/decrease | | Soak Test | Long-term stability | Extended duration |
HTTP Testing
Basic Requests
import http from 'k6/http';
import { check, sleep } from 'k6';
export default function () {
// GET request
const getRes = http.get('https://api.example.com/users');
check(getRes, {
'GET succeeded': (r) => r.status === 200,
'has users': (r) => r.json('data.length') > 0,
});
// POST request with JSON body
const postRes = http.post('https://api.example.com/users',
JSON.stringify({ name: 'Test User', email: 'test@example.com' }),
{
headers: {
'Content-Type': 'application/json',
'Authorization': 'Bearer ' + __ENV.API_TOKEN,
},
}
);
check(postRes, {
'POST succeeded': (r) => r.status === 201,
'user created': (r) => r.json('id') !== undefined,
});
sleep(1);
}
Request Chaining
import http from 'k6/http';
import { check } from 'k6';
export default function () {
// Login and extract token
const loginRes = http.post('https://api.example.com/login',
JSON.stringify({ email: 'test@example.com', password: 'password123' })
);
const token = loginRes.json('access_token');
// Use token in subsequent requests
const headers = {
'Authorization': `Bearer ${token}`,
'Content-Type': 'application/json',
};
const profileRes = http.get('https://api.example.com/profile', {
headers: headers,
});
check(profileRes, {
'profile loaded': (r) => r.status === 200,
});
}
Parameterized Testing
import http from 'k6/http';
import

