How to make a website blazing fast with Lighthouse

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In the competitive world of the internet, website speed is a crucial factor for user experience, SEO rankings, and overall business success. Google Lighthouse is a powerful tool for auditing and improving website performance. This article will guide you step-by-step on how to make your website blazing fast using Google Lighthouse.

What is Google Lighthouse?

Google Lighthouse is an open-source, automated tool for improving the quality of web pages. It provides audits for performance, accessibility, progressive web apps, SEO, and more. You can run it against any web page, public or requiring authentication, and it will generate a report on how well the page performs.

How to Use Google Lighthouse

Step 1: Running a Lighthouse Audit

You can run a Lighthouse audit in several ways:

  • Chrome DevTools: Open Chrome DevTools (F12), go to the "Lighthouse" tab, and click "Generate report".
  •  Lighthouse CLI: Install Lighthouse as a Node module (npm install -g lighthouse) and run it from the command line (lighthouse <url>).
  • PageSpeed Insights: Visit PageSpeed Insights and enter your URL.

Step 2: Understanding the Lighthouse Report

Lighthouse provides a comprehensive report divided into several categories:

  • Performance
  • Accessibility
  • Best Practices
  • SEO

For the purpose of speed optimization, we will focus on the Performance section.

Performance Audit Steps

1. First Contentful Paint (FCP)

FCP measures when the browser renders the first piece of DOM content. To improve FCP:

  • Minimize Render-blocking Resources: Ensure CSS and JavaScript are non-blocking.
  • Use Lazy Loading: Defer loading of offscreen images and iframes.
  • Optimize Fonts: Use font-display: swap to ensure text is visible while fonts are loading.

2. Speed Index

The Speed Index measures how quickly content is visually displayed. To improve it:

  • Minimize Main-thread Work: Reduce JavaScript execution time.
  • Reduce JavaScript Payloads: Minify and compress your scripts.
  • Implement Critical CSS: Inline critical CSS for above-the-fold content.

3. Largest Contentful Paint (LCP)

LCP marks the point when the largest content element in the viewport is rendered. To improve LCP:

  • Optimize Images: Use next-gen formats (like WebP), compress, and resize images.
  • Optimize Web Fonts: Load fonts asynchronously to avoid blocking the rendering.
  • Improve Server Response Times: Use a fast web server and optimize backend processes.

4. Time to Interactive (TTI)

TTI measures how long it takes for the page to become fully interactive. To improve TTI:

  • Minimize JavaScript: Reduce the impact of third-party code.
  • Defer Unused JavaScript: Only load JavaScript when needed.
  • Reduce Request Count and Payload Sizes: Use a CDN and cache assets to reduce load times.

5. Total Blocking Time (TBT)

TBT quantifies the total time that a page is blocked from responding to user input. To improve TBT:

  • Avoid Long Tasks: Break up long JavaScript tasks into smaller ones.
  • Optimize Third-party Scripts: Ensure third-party scripts are non-blocking.
  • Code Splitting: Split your code into smaller chunks to reduce the load.

6. Cumulative Layout Shift (CLS)

CLS measures visual stability and how often users experience unexpected layout shifts. To improve CLS:

  • Specify Size Attributes for Media: Always include width and height size attributes for images and videos.
  • Reserve Space for Ads: Ensure ads don’t cause content shifts.
  • Avoid Injecting Content Above Existing Content: Add new UI elements below the fold or in a dedicated space.

Monitoring Your Performance

To continuously monitor your website's performance, tools like speed.larger.io can be very useful. They help you track Google Lighthouse results over time, ensuring your website maintains optimal speed and performance.

Additionally, PageSpeed Insights remains an essential tool, offering easy access to Lighthouse reports and actionable insights for ongoing optimization.

Conclusion

Using Google Lighthouse for website speed optimization is an effective way to ensure your website provides a fast and seamless user experience. By following the detailed steps in the performance audit and regularly monitoring your site's performance with tools like speed.larger.io and PageSpeed Insights, you can keep your website blazing fast and competitive in today's digital landscape.

Implement these strategies today to see an immediate improvement in your website's performance and user satisfaction.

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