Web perfomance glossary

Compression refers to the technique of reducing the size of files transmitted between servers and clients - such as HTML, CSS, JavaScript, and media content - without losing the original data quality. This process enhances load times by minimizing the amount of data that needs to be sent over the internet. Efficient compression practices ensure quicker page loads, reduced bandwidth usage, and an overall smoother user experience on websites. It's akin to packing a suitcase by removing excess air from each item, allowing more content to fit within the limited space of a web request.

Image optimization involves adjusting and compressing web images to reduce their file size without significantly affecting their visual quality. This process helps improve page load times, enhances user experience, and conserves bandwidth. Techniques used in image optimization include scaling down image resolutions, using efficient file formats (like JPEG, PNG, or WebP), and applying compression algorithms. Effective image optimization balances image quality and file size to ensure images load quickly while still looking good on a variety of devices.

Lazy loading is a technique to delay the loading of non-critical resources at page load time. Instead, these resources are only loaded when they are needed, typically as they come into the viewport or due to user interaction. This approach reduces initial load time, minimizes bandwidth usage, and improves user experience by speeding up page rendering. Lazy loading is commonly applied to images, videos, and scripts, enhancing the performance of websites, especially those with rich content.