Web Performance In Practice: Master Core Web Vitals & More

We run a performance analysis on this page and implement fixes to improve the score toward 100%, covering setup steps from fork and clone to live server testing.

Publish your local project to Firebase hosting to enable online performance testing with Lighthouse, following steps to install Firebase tools, log in, initialize, configure hosting, and deploy.

Analyze local and online project performance with page speed insights, identify core web vitals issues like slow largest contentful paint and high cls, and plan image, font, and script optimizations.

Use the network tab to spot oversized images and bottlenecks that affect the largest contentful paint. Optimize images per device and load off-screen assets on demand to improve performance.

Learn to optimize web images to support core web vitals by defining correct dimensions for mobile, tablet, and desktop, implementing responsive and lazy loading, and preparing assets for performance.

Convert images to webp, compress them, and replace in the project to improve mobile performance; deploy updates and compare page speed insights, reducing largest contentful paint from 16.5s to 3.5s.

Learn how to implement responsive images with the HTML picture element, using breakpoint-specific sources to load one image at a time and improve performance for mobile, tablet, and desktop.

Stage changes in the source control tab, commit with a clear message, and push to view a historical record of performance improvements and image optimizations using webp and picture elements.

Set explicit width and height for all images to reserve space and prevent cls. Define desktop, tablet, and mobile dimensions (1920x893, 960x770, 576x576) to preserve aspect ratio.

Avoid layout shifts by loading dynamic content without hiding elements, using opacity to reserve space for the country and vat bar, or render it empty until data arrives.

Enable lazy loading for product images using the loading attribute to defer off-viewport downloads, reduce requests, and mitigate heavy JavaScript processing in the product section.

Reduce initial JavaScript execution time by lazy loading products not visible on page load as users scroll, using onload, onscroll, and bounding client rect to load once.

Learn to reduce render-blocking resources by self-hosting fonts: define @font-face for hebo with weights 300, 400, 600, 700, use font-display swap, and add a sans-serif fallback.

Defer non-essential services, including the cookie script, using the DOMContentLoaded event and the defer attribute, moving scripts to the body, and test performance with Firebase.

Fix accessibility issues by adding meaningful alt attributes to images, including decorative ones with empty alt, and improving contrast for buttons and links to boost accessibility scores.

Adjust the heading order by using a single h1 for the hero, switch category titles to h2, and convert lower headings to paragraphs; update css and test for accessibility.

Fixes best practices and SEO issues by correcting image aspect ratio with width and height in CSS, replacing a low-resolution icon, and adding a meta description for SEO.

Apply the web performance roadmap to drive continuous improvement by enforcing best practices, monitoring performance, and involving code reviews and QA analysis across the team.

Enforce best practices by building a knowledge base and providing regular training, using Google Docs or Confluence with Jira integration for reporting and checklists for developers and testers.

Monitor website performance with Google Search Console and PageSpeed Insights. Track historical data and alerts to improve SEO and core web vitals, including LCP and CLS across many URLs.

Discover GTmetrix, a tool that monitors website performance with daily or hourly reports, alerts, and pricing options, and learn to run a Lighthouse-based analysis with web vitals and waterfall views.

Explore Gtmetrix history charts to monitor performance over time, compare metrics like largest contentful paint across reports, and identify issues from releases using retest and dashboard insights.

Learn to monitor web performance with GTmetrix, set hourly monitoring, and configure alerts for core web vital metrics like largest contentful paint (LCP) to diagnose issues.

Compare GTmetrix reports to identify performance changes, using the comparison and waterfall views to spot resource loading differences, such as image regressions and LCP gaps.

Foster a collaborative performance culture by involving designers, developers, and QA analysts in resource allocation. Implement code reviews and test workflows with Jira and GTmetrix to detect performance issues early.