Core Web Vitals

Preact

Preact is a fast, 3KB alternative to React that implements the same modern API — components, hooks, and virtual DOM — in a much smaller package, often as a dro…

Progressive Web App (PWA)

A Progressive Web App (PWA) is a website built with modern web APIs to behave like a native app — installable, capable of offline use, and able to send push no…

Service Worker

A service worker is a JavaScript script that a browser runs in the background, separate from a web page, enabling features like offline caching, push notificat…

SEO

SEO (Search Engine Optimization) is the practice of improving a website's structure, content, and technical performance so it ranks higher in search engine res…

Core Web Vitals

Core Web Vitals are a set of standardized metrics defined by Google that measure real-world user experience on a webpage — specifically loading performance, in…

Lighthouse

Lighthouse is an open-source, automated auditing tool built by Google that analyzes a webpage and generates scored reports covering performance, accessibility,…

Content Delivery Network (CDN)

A Content Delivery Network (CDN) is a geographically distributed network of servers that caches and delivers web content — such as images, scripts, and static…

Chrome DevTools

Chrome DevTools is the built-in set of web developer tools in Google Chrome for inspecting, debugging, and profiling HTML, CSS, and JavaScript directly in the…

What is Lazy Loading?

Lazy loading is the technique of deferring the loading of a resource — an image, a script chunk, or a component — until it is actually needed, instead of loadi…

What Is the Critical Rendering Path?

The critical rendering path is the sequence of steps a browser must complete — parsing HTML into a DOM, parsing CSS into a CSSOM, combining them into a render…

What Are Core Web Vitals — LCP, FID/INP, and CLS?

Core Web Vitals are Google's three user-centric metrics for real-world page quality — Largest Contentful Paint (LCP) measures loading speed of the biggest visi…

What Are Key Image Optimization Techniques for the Web?

Web image optimization combines choosing efficient formats (WebP/AVIF), serving correctly sized responsive images via srcset, lazy-loading offscreen images, an…

What Are Resource Hints (preload, prefetch, preconnect)?

Resource hints are HTML/HTTP directives such as preload, prefetch, preconnect, and dns-prefetch that tell the browser to start network work — connecting, resol…

How Do You Manage Third-Party Script Performance?

Third-party scripts (analytics, ads, chat widgets, A/B testing tags) hurt performance by blocking the main thread with parser execution, adding render-blocking…

How Do Lighthouse Audits Work and What Do They Measure?

Lighthouse is an automated auditing tool that loads a page in a controlled, throttled environment and scores it across Performance, Accessibility, Best Practic…

What Is a Web Performance Budget?

A performance budget is a set of measurable limits — such as maximum bundle size, request count, or a target Time to Interactive — that a team agrees not to ex…

What Is the Time to Interactive (TTI) Metric?

Time to Interactive (TTI) is the point at which a page has rendered its content and the main thread is quiet enough that the browser can reliably respond to us…

What Is First Contentful Paint (FCP)?

First Contentful Paint (FCP) is the time from navigation start until the browser renders the first piece of DOM content — text, an image, a non-white canvas, o…

What Is Total Blocking Time (TBT)?

Total Blocking Time (TBT) sums up the portion of every main-thread task, between First Contentful Paint and Time to Interactive, that exceeds 50 milliseconds —…

What Is the Speed Index Metric?

Speed Index measures how quickly the visible content of a page is painted during load by scoring the visual completeness of the viewport at every recorded fram…