Performance Testing with k6

Are your applications fast enough for real users - or are you just hoping they are?

Performance Testing with k6 is the practical, hands-on guide that takes you from complete beginner to confident performance engineer. Written for developers, QA engineers, and DevOps professionals, this book teaches you how to find performance bottlenecks before your users do - using k6, one of the fastest-growing open-source performance testing tools available today.

Unlike theoretical textbooks, every concept in this book is taught through clear, working JavaScript code examples that you can run immediately. You will learn by doing - writing real load tests, interpreting real results, and fixing real performance problems.

What you will learn:

• How to write k6 load tests from scratch using JavaScript - no prior k6 experience needed
• Load testing, stress testing, spike testing, and soak testing - when to use each and how to design them
• How to define thresholds that automatically pass or fail your tests in CI/CD pipelines
• Integrating k6 with GitHub Actions, GitLab CI, Jenkins, and CircleCI for automated performance gates
• Visualising live test results with Grafana and InfluxDB dashboards
• Testing WebSockets, gRPC services, and real browser interactions including Core Web Vitals
• Running globally distributed tests with k6 Cloud and the Kubernetes Operator
• Five complete real-world case studies covering e-commerce, payments APIs, chat services, and more

By the end of this book you will have a fully automated performance testing program integrated into your development workflow - catching regressions before they reach production, protecting your users from slow and unreliable software, and giving your team the confidence to deploy faster.

This book is for you if:

• You are a developer, QA engineer, or DevOps professional who wants to master performance testing
• You know JavaScript basics but have never written a performance test before
• You have tried other performance testing tools and found them too complex or too rigid
• You want to integrate automated performance validation into your CI/CD pipeline

Covering 15 structured chapters, 100+ working code examples, and a 30-day action plan, this is the most complete k6 resource available - your definitive reference for performance testing modern web applications.