PageSpeed Insights: how to keep site speed high

If you run a website, you have probably heard of Google PageSpeed Insights. It is a free tool from Google that measures the performance of your web pages on both mobile and desktop devices. But getting a high score can often feel like a game you cannot win.

Today we are going to do a detailed review of PageSpeed Insights, look at all the possible problems that bring your score down, and explain exactly how to optimize your website.

Why is site speed so important?

Before we look at the technical problems, let’s talk about why you should care. Site speed is not just a vanity metric. It directly impacts your business.

First, speed is a major ranking factor for SEO. Google has stated officially that they use Core Web Vitals to decide how high your pages rank. If your site takes too long to load, Google will push you down the search results.

Second, speed impacts user experience and conversion rates. Most users will abandon a page if it takes more than three seconds to appear. A fast site keeps visitors engaged and makes them much more likely to buy your product or read your articles.

Understanding PageSpeed Insights metrics

When you type a URL into PageSpeed Insights, it gives you two types of data: lab data and field data.

Field data shows how real users experience your site. It is collected over 28 days using the Chrome User Experience Report (CrUX). This is what really matters for your SEO. Lab data is collected in a controlled environment to help you debug problems.

The main metrics to watch are:

• First contentful paint (FCP): the time it takes for the browser to render the first piece of text or image.
• Largest contentful paint (LCP): the time it takes for the biggest block of content to become visible.
• Cumulative layout shift (CLS): measures how much your page layout shifts around as it loads.
• Interaction to next paint (INP): how quickly your page responds after a user clicks or taps something.

Common problems that ruin your score

Getting a bad score is easy. Fixing it requires finding the root cause. Here are the most common problems you will see in your PageSpeed Insights diagnostic report.

1. Render-blocking resources

This happens when you have javascript or CSS files completely blocking the page from loading. The browser has to stop, download the file, and parse it before it can show anything to the user. How to fix: you should defer or asynchronously load all non-critical javascript. For CSS, extract the critical CSS and inline it in the target , then load the rest asynchronously.

2. Unoptimized huge images

Images usually make up the largest part of a webpage total weight. Uploading a 5MB image for a small logo is a guaranteed way to slow everything down. How to fix: always compress your images using modern formats like WebP. You should also use the loading="lazy" attribute so images below the fold are only loaded when the user scrolls down to them. Always set explicit width and height on image tags to prevent layout shifts.

3. Too much unused javascript

Modern websites often load heavy libraries or third party scripts, but only use a small fraction of the code. The browser still has to download and evaluate everything, taking up valuable processing time. How to fix: remove unused plugins and try to split your code. Only load the scripts you actually need on that specific page.

4. Slow server response times

Time to first byte (TTFB) measures how long it takes your hosting server to return the initial HTML. If your server is slow, all the other optimizations won’t matter much. How to fix: use a fast web host. Implement server side caching and use a content delivery network (CDN) to serve your site from servers physically closer to your users.

This tool is great, because it says where exactly you made a mistake and even show you exact screenshots. So just fix those errors step by step, and your SEO will be improved.

It suggested to convert .jpg to .webp images for our website, for example.

But do not be upset if you can not reach 100%, it is actually really hard to do. If your website is complex, need a lot of images, some specific js libraries, you may think – there is nothing to optimize anymore, why my score still is 80-90% ? This is absolutely normal. If your website is in the “green zone”,  that is already a good sign. Furthermore, results may even vary by a few percentage points – without any changes whatsoever – if you test the speed at a different time.
However, you should still try to maximize your performance by going through and fixing every error in the list.

Why our translation script keeps your speed high

When adding new widgets to your website, you have to be very careful about performance. It is very common for translation plugins to destroy your PageSpeed score. They often load massive language databases on the client side, run heavy javascript delays, and block rendering while they figure out what language to display.

We built our translation script strictly with performance in mind. Here is why our solution is lightweighted and has minimal affect on the performance speed:

• Tiny payload limit: our core script is incredibly small. We do not bundle large third party libraries. It adds just few kilobytes to your page size.
• Asynchronous loading: the script is designed to run asynchronously. It never blocks your main content from rendering.
• Global CDN delivery: we deliver the script and the translated text from a global network. This means the data travels the shortest possible distance to your visitor.
• Native DOM injection: instead of hiding the page or creating layout shifts, our script natively injects translated strings seamlessly. It executes in milliseconds, so your cumulative layout shift stays perfectly at zero.

By keeping the technical footprint as small as possible, we ensure that you can translate your website entirely without sacrificing any of your hard earned SEO rankings or user experience.