The Ultimate Guide to Web Performance Optimization

It is the world of immediate satisfaction. With a loading time of over 3 seconds, half of all mobile users will leave immediately. Performance is not merely a nice to have in the digital era, but a part and parcel.

Slow site is bad to your User Experience (UX), kills your conversion rates and even kills your Google Search ranking (SEO). How do we get the lightning fast sites then? We must be able to learn the measures and the maximizations.

1. The Core Web Vitals Measuring Success

It is impossible to measure what you can not fix. Google evaluates your site using three so-called Core Web Vitals.

Largest Contentful Paint (LCP) - Speed of loading. Waiting time of the main content (such as the hero image or the headline) is how long does it take? (Target - Under 2.5s)

Interaction to Next Paint (INP) - Interactivity. How much time does it take to get a response when a user clicks on a button? When it is frozen, then you have a high INP. (Target - Under 200ms)

Cumulative Layout Shift (CLS) - Visual Stability. Is the page jumpy when loading? It is the most annoying when one is trying to click on a link and an advertisement appears above it and shifts the link downwards. (Target - Under 0.1)

2. Heavy Lifters - Photographs and Media

The most contentious element of any webpage is normally images. The low-hanging fruit of performance is to optimize them.

• Compression - The raw images should never be offered. With help of such tools as TinyPNG or ImageOptim, one can remove all the unnecessary information without quality loss.
• Contemporary Formats - Photos should no longer be in the use of PNGs. Instead, use WebP or AVIF, which is of higher quality with the fraction of the file size.
• Lazy loading - Why download the images at the bottom of the page when the user has not scroll to the bottom yet? Load loading with lazy and only download the images when they are in the viewport.

3. Minification and Bundling - Cutting the Fat

There are too many characters with humanistic code (HTML, CSS, JS) even spaces, comments, and names of variables that are very long. Computers don't need these.

Minification removes white space and shortens the names of variables (e.g. const userPassword is renamed const a). This radically cuts down the size of the file. Bundling is a technique of taking several small files and putting them together to form one large file so that the browser does not need to make several network requests.

4. Caching and CDNs - Location, Location, Location.

The speed of light is rapid but it is not endless. As your user is in Tokyo and your server is in New York, data must travel half way across the globe.

• Browser Caching - Instruct the browser of the user, Hey, this logo has not changed. Store it in the hard disk and this way you need not download again the next time.
• Content Delivery Networks (CDNs) - A CDN replicates your site (static resources, images, CSS, etc.) to servers across the globe. A user in Tokyo comes to your site, downloads the pictures on a server in Tokyo, not New York.

Summary

It is a Journey on Performance. Web performance is not something that can be cured once, it is a process. You will find that when you add new features, marketing scripts your site will shrink. Periodic reviews (to such tools as Google Lighthouse) are necessary.