Performance Best Practices

Here’s a comprehensive list of frontend performance best practices — covering everything from loading optimization to runtime efficiency and tooling.

Images & Media

  • Use WebP or AVIF instead of PNG/JPEG
  • Use responsive images (srcset, sizes)
  • Lazy-load offscreen images (loading="lazy")

Measure & Monitor

  • Use web-vitals library to measure and monitor performance
  • Use Lighthouse to audit performance
  • Use GTmetrix to analyze performance
  • Use Google PageSpeed Insights to analyze performance

Other

  • Optimize Images: Compress and resize images to reduce file size without sacrificing quality. Use modern formats like WebP for better compression.
  • Minimize HTTP Requests: Reduce the number of requests by combining files, using CSS sprites, and minimizing the use of scripts and plugins.
  • Use a Content Delivery Network (CDN): CDNs distribute your content across multiple servers worldwide, reducing the distance between the server and the user, thus improving load times.
  • Enable Caching: Set appropriate caching policies to store frequently accessed resources on the user's device, reducing load times on subsequent visits.
  • Minify and Combine Files: Minify CSS, JavaScript, and HTML by removing unnecessary characters and spaces. Combine multiple files into one where possible to reduce the number of HTTP requests.
  • Use Asynchronous Loading for CSS and JavaScript: Load non-critical CSS and JavaScript files asynchronously to prevent them from blocking the rendering of the page.
  • Optimize CSS and JavaScript: Streamline and optimize code. Remove unused CSS and JavaScript to reduce file size.
  • Implement Lazy Loading: Load images and other resources only when they are needed (as the user scrolls down), which can significantly reduce initial load times.
  • Optimize Web Fonts: Limit the use of different font styles and weights, and use font-display settings to control how fonts are loaded.
  • Improve Server Response Time: Optimize your server, consider using a dedicated or virtual private server, and look into server-side caching.
  • Use Compression: Enable compression on your web server to reduce the size of your CSS, HTML, and JavaScript files.
  • Optimize Database Queries: For websites relying on a database, optimize queries and use indexing to speed up data retrieval.
  • Audit with Tools: Regularly use tools like Google PageSpeed Insights, Lighthouse, and GTmetrix to analyze and improve performance.
  • Mobile Optimization: Ensure your website is responsive and optimized for mobile devices, as more users are browsing on mobile.
  • Reduce Redirects: Each redirect triggers an additional HTTP request-response cycle, so minimize them to improve load times.