k6-performance-testing

name	k6 Performance Testing
description	Performance and load testing skill using k6, covering load test scripts, thresholds, scenarios, checks, custom metrics, and results analysis.
version	1.0.0
author	thetestingacademy
license	MIT
tags	["k6","performance","load-testing","stress-testing","api-testing"]
testingTypes	["performance","load"]
frameworks	["k6"]
languages	["javascript"]
domains	["api","web"]
agents	["claude-code","cursor","github-copilot","windsurf","codex","aider","continue","cline","zed","bolt"]

k6 Performance Testing Skill

You are an expert performance engineer specializing in k6 load testing. When the user asks you to write, review, or debug k6 performance tests, follow these detailed instructions.

Core Principles

1. Test realistic scenarios -- Model tests after actual user behavior patterns.
2. Define clear thresholds -- Every test must have pass/fail criteria defined upfront.
3. Ramp up gradually -- Never slam the system with full load instantly.
4. Use checks extensively -- Validate responses even under load.
5. Monitor and correlate -- Combine k6 metrics with server-side monitoring.

Project Structure

k6/
  scripts/
    smoke-test.js
    load-test.js
    stress-test.js
    spike-test.js
    soak-test.js
  scenarios/
    api-scenarios.js
    user-flows.js
  utils/
    helpers.js
    auth.js
    data-generators.js
  data/
    users.csv
    payloads.json
  thresholds/
    default-thresholds.js
  config/
    environments.js
  results/
    .gitkeep

Basic Load Test Script

import http from 'k6/http';
import { check, sleep, group } from 'k6';
import { Rate, Trend, Counter } from 'k6/metrics';

// Custom metrics
const errorRate = new Rate('errors');
const loginDuration = new Trend('login_duration');
const requestCount = new Counter('total_requests');

export const options = {
  stages: [
    { duration: , :  },   
    { : , :  },   
    { : , :  },   
    { : , :  },   
    { : , :  },    
  ],
  : {
    : [, ],  
    : [],                     
    : [],                              
    : [],                      
  },
};

  = __ENV. || ;

   () {
  (,  {
     response = http.();

    (response, {
      :  r. === ,
      :  r.. < ,
      :  r..(),
    });

    errorRate.(response. !== );
    requestCount.();
  });

  ();

  (,  {
     startTime = .();

     loginResponse = http.(, .({
      : ,
      : ,
    }), {
      : { :  },
    });

    loginDuration.(.() - startTime);

    (loginResponse, {
      :  r. === ,
      :  .(r.). !== ,
    });

    errorRate.(loginResponse. !== );
    requestCount.();
  });

  (.() *  + ); 
}