Performance guides

Performance · 9 min read

Brotli and Gzip Compression: Turn It On and Verify It

Turn on Brotli or gzip for HTML, CSS and JavaScript, choose the right file types and levels, and verify the Content-Encoding and Vary headers with curl.

Performance · 9 min read

Cache-Control Headers: How to Cache Static Files Safely

Set Cache-Control headers so browsers and CDNs reuse static files, keep HTML fresh, avoid stale CSS and personal pages in shared caches, and verify the result.

Performance · 10 min read

CDN for SEO: Set Up a CDN Without Breaking Crawling

Set up a CDN for speed, choose what to cache, keep Googlebot and Bingbot able to crawl, and verify cache headers, status codes and bot access afterwards.

Performance · 9 min read

Core Web Vitals Explained: LCP, INP and CLS Thresholds

Learn what the three Core Web Vitals measure, the good and poor thresholds, why field and lab numbers differ, and how to read your results and plan fixes.

Performance · 8 min read

Core Web Vitals Report in Search Console: Read It and Prioritize Fixes

Understand how the Search Console Core Web Vitals report groups URLs, why it shows no data, and how to rank fixes and track them over a 28-day window.

Performance · 10 min read

Critical CSS: Inline What Matters and Defer the Rest

Learn when critical CSS is worth the effort, how to extract above-the-fold styles, inline them in the head, load the rest later and test for flashes.

Performance · 10 min read

Field Data vs Lab Data: Why Lighthouse and Real Users Disagree

Compare Lighthouse lab results with Chrome UX Report field data, understand why they differ metric by metric and decide which one to act on.

Performance · 3 min read

Fix Largest Contentful Paint (LCP) on Mobile

Identify your page's LCP element, then fix slow server response, late discovery and oversized images, and retest in lab and field data on mobile.

Performance · 9 min read

Font Display Swap: Load Web Fonts Without Layout Shift

Choose the right font-display value, preload key fonts, subset to WOFF2 and match fallback sizes so web fonts load fast without text jumping on screen.

Performance · 9 min read

HTTP/2 and HTTP/3: What Changes for Speed and How to Check

See what HTTP/2 and HTTP/3 change, check which protocol your site uses with DevTools and curl, turn them on safely and know what they will not fix.

Performance · 2 min read

Improve Interaction to Next Paint (INP) on JavaScript Sites

Find which clicks, taps and keystrokes feel slow, trace the long JavaScript tasks behind them, shorten the work and recheck INP on real devices.

Performance · 2 min read

Improve Lighthouse Performance Without Breaking Your Website

Set a repeatable Lighthouse baseline, find the main bottleneck, make small safe fixes and compare repeated runs without breaking your site.

Performance · 11 min read

Lazy Load Iframes and Video Embeds Without Hurting the Page

Defer YouTube video and map iframes with loading=lazy, reserve space to avoid layout shift, add a click-to-load facade and test what Google can see.

Performance · 8 min read

Lazy Loading Images for SEO: Defer Images Without Hiding Them

Lazy-load below-the-fold images with the native loading attribute, keep above-the-fold and LCP images eager, and test that Google still sees them.

Performance · 10 min read

Lighthouse CI and Performance Budgets: Catch Regressions Early

Set up Lighthouse CI in your build, write a lighthouserc file with assertions and size budgets, and fail pull requests that slow the site down.

Performance · 2 min read

Mobile Lighthouse Score Lower Than Desktop? Fix the Right Issues

Learn why the mobile Lighthouse score is usually lower than desktop, then compare like-for-like runs and fix oversized images, scripts and slow requests.

Performance · 9 min read

Mobile Usability: Fix Viewport, Tap Targets and Readable Text

Set the viewport meta tag, size and space tap targets, stop horizontal scrolling and keep text readable and zoomable, with tests you can run on a phone.

Performance · 10 min read

Mobile-First Indexing Checklist: Make the Mobile Version Complete

Check that your mobile pages carry the same content, links, structured data and robots rules as desktop, and test them with Search Console and DevTools.

Performance · 2 min read

Reduce Cumulative Layout Shift (CLS) Step by Step

Find what makes your page jump while it loads, then reserve space for images, embeds, banners and fonts and retest CLS on mobile and desktop.

Performance · 10 min read

Reduce JavaScript Bundle Size: Measure, Split and Remove Code

Find what fills your JavaScript bundle, remove unused code, split by route with dynamic import, and check the result with Lighthouse and DevTools.

Performance · 2 min read

Remove Render-Blocking CSS and JavaScript Safely

Identify the CSS and scripts that delay first paint, split critical from optional code, apply defer or async where safe and test menus and forms.

Performance · 11 min read

Responsive Images with srcset and sizes: Serve the Right Size

Write srcset and sizes correctly, use picture for art direction and formats, set width and height, and verify that phones download smaller files.

Performance · 9 min read

Third-Party Scripts and Performance: Measure and Tame Them

List every third-party tag, chat widget and ad script, measure what each costs your page, then remove, delay or isolate the ones that slow it down.

Performance · 10 min read

Time to First Byte (TTFB): Measure It and Fix a Slow Server

Measure time to first byte, split it into redirect, connection and server time, then cut each part with caching, fewer redirects and faster back-end work.