Environment variables
k6 can access environment variables at runtime. You can use environment variables to:
- Configure test behavior without modifying the script
- Pass sensitive data like API keys
- Parameterize tests for different environments
- Override k6 options
Accessing environment variables
Access environment variables in your script using the __ENV object:
import http from 'k6/http';
const BASE_URL = __ENV.BASE_URL || 'https://test-api.k6.io';
const API_KEY = __ENV.API_KEY;
export default function () {
const headers = {
'Authorization': `Bearer ${API_KEY}`,
};
http.get(`${BASE_URL}/public/crocodiles/`, { headers });
}
Setting environment variables
You can set environment variables in multiple ways:
Command line
.env file
System environment
Pass variables when running k6:BASE_URL=https://api.example.com API_KEY=secret k6 run script.js
Create a .env file:# .env
BASE_URL=https://api.example.com
API_KEY=your-api-key-here
export $(cat .env | xargs) && k6 run script.js
Set system-wide environment variables:export BASE_URL=https://api.example.com
export API_KEY=secret
k6 run script.js
k6 options via environment variables
You can set k6 options using environment variables with the K6_ prefix:
K6_VUS=10 K6_DURATION=30s k6 run script.js
Test duration (e.g., 30s, 5m, 1h)
Total number of iterations
Output destination (e.g., json=results.json, influxdb=http://localhost:8086)
K6_INSECURE_SKIP_TLS_VERIFY
Skip TLS certificate verification
Common patterns
Environment-specific configuration
import http from 'k6/http';
const ENV = __ENV.ENV || 'dev';
const config = {
dev: {
baseUrl: 'https://dev.example.com',
vus: 5,
},
staging: {
baseUrl: 'https://staging.example.com',
vus: 20,
},
prod: {
baseUrl: 'https://api.example.com',
vus: 100,
},
};
export const options = {
vus: config[ENV].vus,
duration: '30s',
};
export default function () {
http.get(`${config[ENV].baseUrl}/api/status`);
}
ENV=staging k6 run script.js
Sensitive data
Never hardcode sensitive data like API keys, passwords, or tokens in your test scripts.
import http from 'k6/http';
import { check } from 'k6';
const API_KEY = __ENV.API_KEY;
const API_SECRET = __ENV.API_SECRET;
if (!API_KEY || !API_SECRET) {
throw new Error('API_KEY and API_SECRET must be set');
}
export default function () {
const res = http.post('https://api.example.com/auth', {
key: API_KEY,
secret: API_SECRET,
});
check(res, {
'authenticated': (r) => r.status === 200,
});
}
Feature flags
import http from 'k6/http';
const ENABLE_BROWSER_TESTS = __ENV.ENABLE_BROWSER_TESTS === 'true';
const ENABLE_WEBSOCKETS = __ENV.ENABLE_WEBSOCKETS === 'true';
export default function () {
http.get('https://test.k6.io');
if (ENABLE_WEBSOCKETS) {
// WebSocket test code
}
// Additional tests based on flags
}
Best practices
Always provide fallback values for non-critical environment variables:const BASE_URL = __ENV.BASE_URL || 'https://test-api.k6.io';
const TIMEOUT = parseInt(__ENV.TIMEOUT) || 30;
Validate required variables
Fail early if required variables are missing:const API_KEY = __ENV.API_KEY;
if (!API_KEY) {
throw new Error('API_KEY environment variable is required');
}
Environment variables are always strings. Convert them as needed:const VUS = parseInt(__ENV.VUS) || 10;
const ENABLE_FEATURE = __ENV.ENABLE_FEATURE === 'true';
const RATE = parseFloat(__ENV.RATE) || 0.5;
Document required variables
Add comments or README documentation listing required environment variables:/**
* Required environment variables:
* - API_KEY: Your API authentication key
* - BASE_URL: Target API base URL
*
* Optional:
* - TIMEOUT: Request timeout in seconds (default: 30)
*/
CI/CD integration
Environment variables are particularly useful in CI/CD pipelines:
name: Load Test
on: [push]
jobs:
test:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- uses: grafana/[email protected]
with:
filename: script.js
env:
BASE_URL: ${{ secrets.BASE_URL }}
API_KEY: ${{ secrets.API_KEY }}
K6_VUS: 50
K6_DURATION: 5m
Options reference
Complete list of k6 options
Automated testing
Integrating k6 with CI/CD