Web Performance
21 articles
Core Web Vitals Explained: How to Test and Improve Them (2026)
What Core Web Vitals are, what counts as a good score for LCP, INP and CLS, how to test your site with free tools, and the highest-impact ways to improve each metric.
How to Test Your Website Speed (Tools and Metrics)
Which tools to use, lab versus field data, and the metrics that matter. Test your site speed with PageSpeed Insights, Lighthouse, WebPageTest and DevTools.
How to Optimize CSS for Faster Pages
CSS is render-blocking, so bloated stylesheets delay your page. How to minify, cut unused CSS, inline critical CSS and defer the rest to speed up FCP and LCP.
What Are Gzip and Brotli Compression (and How to Enable Them)?
Gzip and Brotli shrink HTML, CSS and JavaScript before they are sent. What each is, how Brotli compares to Gzip, how to verify it, and how to enable it.
How to Reduce Server Response Time
Slow server response time delays everything and hurts LCP. The real causes, from unindexed queries to no caching to distant origins, and how to fix each one.
How to Use preload, prefetch, and preconnect (Resource Hints)
Resource hints tell the browser what to fetch and connect to early. When to use preconnect, dns-prefetch, preload, prefetch and modulepreload, and the pitfalls.
What Are HTTP/2 and HTTP/3, and Why They Matter for Speed
HTTP/2 and HTTP/3 fix HTTP/1.1's bottlenecks. What each protocol changes, how multiplexing and QUIC speed loading, and how to check which your site uses.
What Is Render-Blocking and How to Eliminate It
Render-blocking CSS and synchronous JavaScript delay first paint. What it is, how to find it in Lighthouse, and how to eliminate it to improve FCP and LCP.
What Is Browser Caching and How to Set It Up
Browser caching lets visitors reuse files instead of re-downloading them. What it is, the HTTP headers that control it, cache-busting, and how to verify it.
What Is Lazy Loading and How to Use It
Lazy loading defers offscreen resources until needed. What it is, how to use native loading="lazy", when not to lazy-load, and avoiding any layout shift.
How to Optimize Web Fonts for Performance
Web fonts can block rendering, hide text and cause layout shift. How to optimise them with woff2, subsetting, font-display, preloading and self-hosting.
What Is Total Blocking Time (TBT) and How to Reduce It
Total Blocking Time is the lab proxy for interactivity. What TBT is, how it relates to INP, what causes a high score, and how to reduce it by taming JavaScript.
What Is First Contentful Paint (FCP)?
First Contentful Paint marks when a page first shows content. What FCP is, what is good, how it differs from LCP, what causes a slow score, and how to fix it.
What Is Time to First Byte (TTFB) and How to Improve It
Time to First Byte measures how long the browser waits for a server response. What TTFB is, what counts as good, its components, and how to improve it.
How to Reduce JavaScript and Speed Up Your Site
Excessive JavaScript is costly to download and run, hurting INP and LCP. How to reduce it: code-splitting, tree-shaking, defer/async and auditing third parties.
What Is a CDN, and Do You Need One?
A CDN caches your content on edge servers close to users, cutting latency and TTFB. What a CDN does, the main providers, who needs one, and how to spot one.
How to Optimize Images for the Web
Images dominate page weight. How to optimise them with modern formats, compression, correct sizing, responsive images and lazy-loading to speed up your site.
What Is Cumulative Layout Shift (CLS) and How to Fix It
Cumulative Layout Shift measures visual stability: how much a page jumps while loading. What CLS is, what causes it, and how to fix every common source.
What Is Largest Contentful Paint (LCP) and How to Improve It
Largest Contentful Paint measures how fast a page's main content renders. What LCP is, what counts as good, what causes a slow score, and how to improve it.
How to Make Your Website Load Faster: A Practical Guide
A prioritised guide to a faster site: measure first, then cut page weight, optimise the critical path, cache and use a CDN, and reduce server response time.
INP (Interaction to Next Paint) Explained: The Responsiveness Metric
INP replaced FID as a Core Web Vital in 2024. Here is what Interaction to Next Paint measures, what a good score is, what causes poor INP, and how to fix it.