Avoid hiding text while font-files are downloaded. Instead, show content to users immediately using a system font.
Serve images in WebP, JPEG 2000 or JPEG XR formats. Images in these formats are smaller in size as compared to JPEG / PNG formats.
Reliably serve brotli compressed files with gzip fallback while ensuring no compression overhead when serving brotli files.
What is a cache policy and how to set the right HTTP cache policy to serve your static files.
Delay loading images that appear below-the-fold for faster rendering of above-the-fold page content.
Asynchronously load non-critical CSS files with loadCSS to avoid blocking page rendering.
How to use 'font-display' descriptor for a website that uses Google Fonts.
How to lazy load images for faster load times with no negative SEO impact.
Make sure that images hidden through 'display:none' are not downloaded by the browser.
Serve WebP images without browser compatibility issues even when not all of your past website images have WebP version.
Load small background images on smaller screens and large ones on larger screens.