Optimising Web Performance for Better UX

Web performance is a critical aspect of user experience. Studies consistently show that users abandon sites that take too long to load, and search engines like Google factor page speed into their ranking algorithms. In this post, we’ll explore practical strategies to optimize your website’s performance.

Why Performance Matters

Before diving into optimisation techniques, let’s understand why performance is crucial:

• User Experience: 53% of mobile users abandon sites that take longer than 3 seconds to load
• Conversion Rates: A 1-second delay in page load time can result in a 7% reduction in conversions
• SEO: Page speed is a ranking factor for search engines
• Accessibility: Fast websites are more accessible, especially for users with limited bandwidth

Core Web Vitals

Google’s Core Web Vitals are a set of specific factors that Google considers important for a webpage’s overall user experience:

1. Largest Contentful Paint (LCP): Measures loading performance. To provide a good user experience, LCP should occur within 2.5 seconds of when the page first starts loading.

2. First Input Delay (FID): Measures interactivity. Pages should have a FID of less than 100 milliseconds.

3. Cumulative Layout Shift (CLS): Measures visual stability. Pages should maintain a CLS of less than 0.1.

Performance Optimisation Techniques

1. Optimise Images

Images often account for most of the downloaded bytes on a webpage. Optimising them can significantly improve load times:

• Use modern formats like WebP or AVIF
• Implement responsive images with srcset and sizes attributes
• Lazy load images below the fold
• Compress images without sacrificing quality

<img 
  src="small.jpg" 
  srcset="small.jpg 500w, medium.jpg 1000w, large.jpg 1500w" 
  sizes="(max-width: 600px) 500px, (max-width: 1200px) 1000px, 1500px" 
  alt="Description" 
  loading="lazy" 
/>