--- title: "Beginner's Guide to Performance Testing | Evaluat" description: "A free, ordered course in website performance and load testing for developers, QA and ecommerce teams. Two new parts every week, with background reading." url: "https://www.evaluat.com/blog/beginners-guide" last_modified: "2026-09-24" --- [Blog](https://www.evaluat.com/blog) # The beginner's guide to performance testing Ninety short parts that take you from "what is load testing" to reading your own reports, written for developers, QA engineers and ecommerce teams who are new to performance work. Each part stands on its own; read in order and the vocabulary builds. 8parts published so far. New parts every Wednesday and Thursday; the latest is part 8, 24 September 2026. [Start at part 1](https://www.evaluat.com/blog/black-friday-readiness-timeline) Module ## Foundations What performance testing is, why speed matters to a business, and what a first load test looks like. 1. [Part 2 What is website performance, and why does speed matter? Why is website speed important? What website performance really covers, what slow pages cost in conversions and rankings, and how performance is measured.](https://www.evaluat.com/blog/what-is-website-performance) 2. [Part 3 The types of performance testing, and when to use each The types of performance testing explained for beginners: load, stress, spike and soak, plus smoke, capacity, volume and scalability, and which to run when.](https://www.evaluat.com/blog/types-of-performance-testing) 3. [Part 4 What is a virtual user? A virtual user is a simulated visitor in a load test. What VUs actually simulate, how they differ from concurrent users and requests, and the traps to avoid.](https://www.evaluat.com/blog/what-is-a-virtual-user) 4. [Part 6 How to load test a website: your first test, step by step How to do load testing on a website for the first time. Ten steps, from choosing one journey and sizing it from real traffic to reading the final report.](https://www.evaluat.com/blog/how-to-load-test-a-website) Background reading - [What is load testing?](https://www.evaluat.com/blog/what-is-load-testing) - [Performance testing: the complete guide](https://www.evaluat.com/blog/performance-testing-guide) - [Load testing vs stress testing vs performance testing: how the three actually differ](https://www.evaluat.com/blog/load-vs-stress-vs-performance-testing) - [Functional testing vs performance testing: two questions every release should answer](https://www.evaluat.com/blog/functional-testing-vs-performance-testing) - [Smoke testing vs performance testing: when a quick pre-release check is enough](https://www.evaluat.com/blog/smoke-testing-vs-performance-testing) Module ## How a web page loads The journey from a typed URL to a rendered page: DNS, TLS, the first byte, caches, scripts and images, and why mobile is slower. 1. [Part 8 What happens when a web page loads: DNS, TLS, TTFB and render How does a web page load? Seven waits, from DNS lookup and TLS handshake to first byte and render, with what each costs and which grow when a site is busy.](https://www.evaluat.com/blog/how-a-web-page-loads) Module ## Measuring speed Core Web Vitals and the metrics around them, the tools that report them, and how to read a score without being misled by it. Parts in this module are still to come. Background reading - [Largest Contentful Paint (LCP), explained for engineers](https://www.evaluat.com/blog/largest-contentful-paint) - [Interaction to Next Paint (INP), explained for engineers](https://www.evaluat.com/blog/interaction-to-next-paint) - [How to improve LCP: a step-by-step optimization guide](https://www.evaluat.com/blog/how-to-improve-lcp) - [How to improve INP: a step-by-step optimization guide](https://www.evaluat.com/blog/how-to-improve-inp) - [How to improve CLS: a step-by-step optimization guide](https://www.evaluat.com/blog/how-to-improve-cls) - [Core Web Vitals: why lab scores differ from real users](https://www.evaluat.com/blog/core-web-vitals-lab-vs-field) - [Core Web Vitals at load, explained](https://www.evaluat.com/blog/core-web-vitals-load-testing) - [Why average response time misleads you: reading p95 and p99](https://www.evaluat.com/blog/p95-p99-response-time) - [What is an Apdex score? Measuring user satisfaction in performance testing](https://www.evaluat.com/blog/what-is-an-apdex-score) - [8 metrics every performance test report should include](https://www.evaluat.com/blog/performance-test-report-metrics) Module ## Load-testing vocabulary Virtual users, concurrency, throughput, ramp-up and the other words every load test report uses. 1. [Part 7 How many concurrent users can my website handle? (with calculator) Concurrent users are the people on your site at the same moment. The formula, a worksheet calculator, a lookup table, and why capacity must be measured.](https://www.evaluat.com/blog/how-many-concurrent-users) Background reading - [Real-browser load testing, explained](https://www.evaluat.com/blog/real-browser-load-testing) - [API performance testing vs browser performance testing: which your QA strategy needs](https://www.evaluat.com/blog/api-vs-browser-performance-testing) Module ## Types of tests Capacity, volume, scalability and the rest of the testing family, and which shape of test answers which question. 1. [Part 5 What is capacity testing? Capacity testing finds how many users your site can serve while still meeting its speed targets. How it differs from stress testing, and how to run one.](https://www.evaluat.com/blog/what-is-capacity-testing) Background reading - [Soak testing explained: catching slow degradation and memory leaks over time](https://www.evaluat.com/blog/soak-testing) - [What is spike testing? Preparing for traffic surges and flash sales](https://www.evaluat.com/blog/what-is-spike-testing) - [Stress testing a website: how to find the breaking point before your users do](https://www.evaluat.com/blog/stress-testing-a-website) Module ## Running tests safely Sizing, duration, environments, test data, pass criteria and the operational blockers every first test hits. Parts in this module are still to come. Background reading - [Performance regression testing: making Core Web Vitals a CI/CD release gate](https://www.evaluat.com/blog/performance-regression-testing) - [Where does performance testing fit in an agile release cycle?](https://www.evaluat.com/blog/performance-testing-agile-release-cycle) Module ## Reading results Reading a report, spotting results that will not survive production, and explaining the numbers to the people who fund the fix. Parts in this module are still to come. Module ## Where slowness comes from Where sites actually slow down under load: databases, caches, third-party services, autoscaling limits and queues. Parts in this module are still to come. Module ## Ecommerce and peak season Peak-season readiness for online stores: Black Friday planning, flash sales, checkout and platform-specific slowdowns. 1. [Part 1 How to prepare your website for Black Friday: the 12-week plan Black Friday website preparation as a 12-week countdown: size your peak from last year, load test early, fix, rehearse the spike, freeze, and stand watch.](https://www.evaluat.com/blog/black-friday-readiness-timeline) Background reading - [Why Magento checkout dies first under load](https://www.evaluat.com/blog/magento-checkout-slow-under-load) - [Why your Shopify store slows down under load](https://www.evaluat.com/blog/shopify-store-slow-under-load) - [WooCommerce performance testing: find your store's limit under load](https://www.evaluat.com/blog/woocommerce-performance-testing) - [Load testing a headless or Hyvä storefront](https://www.evaluat.com/blog/load-testing-headless-hyva-storefront) Module ## Tools and capstone Choosing and comparing tools, plus the reference material that ties the guide together. Parts in this module are still to come. Background reading - [Best real-browser load testing tools in 2026](https://www.evaluat.com/blog/best-real-browser-load-testing-tools) - [Playwright for performance testing: can a browser automation tool drive virtual users?](https://www.evaluat.com/blog/playwright-performance-testing) See it on your site Test in real browsers.\ Debug in real sessions. ## Want the guide applied to your own site? 30 minutes. We build a scenario on your real customer journey, run a small test, and walk you through the report. [Book a demo](https://www.evaluat.com/demo?intent=performance) [How it works](https://www.evaluat.com/how-it-works)