Page Speed Insights

Google PageSpeed Insights is a tool developed by Google that analyses the loading speed of websites and provides recommendations for optimisation. In today’s world where internet connection speed is crucial, this service is an extremely useful resource for developers and site owners.

How does Google PageSpeed Insights work?

Page analysis

The tool performs a speed analysis of a website, examining various factors affecting its performance, such as loading time, rendering or interactivity. After entering the URL of a page, PageSpeed Insights generates a report that includes results for both desktop and mobile versions.

Performance evaluation

PageSpeed Insights evaluates the performance of a page based on a score between 0 and 100, where higher values indicate better performance. The score is classified into three categories:

1. Good (green): 90-100
2. Moderate (yellow): 50-89
3. Poor (red): 0-49

Optimisation recommendations

After analysis, Google PageSpeed Insights provides recommendations for improving page speed. These recommendations are divided into two categories: optimisations that have already been applied and those that can still be implemented. The recommendations cover various aspects, such as file compression, image optimisation or minimising CSS and JavaScript code.

Core Web Vitals: key website performance indicators

Core Web Vitals are a set of three key metrics developed by Google to assess the quality of the user experience on websites. These metrics focus on three main areas: page loading, interactivity and visual stability. Google includes these metrics in its ranking algorithm, making them important for both developers and site owners.

Core Web Vitals

1. Largest Contentful Paint (LCP)

Largest Contentful Paint (LCP) is a metric that measures how long it takes for the most important elements of a page’s content, such as images, backgrounds or blocks of text, to load. LCP assesses how long it takes before a user sees the most important content on a page.

Good LCP values are those below 2.5 seconds. Values between 2.5 and 4 seconds are moderate, and above 4 seconds are considered poor.

2. First Input Delay (FID)

First Input Delay (FID) measures the time between a user’s first interactive action on a page (clicking, scrolling, etc.) and when the browser is able to respond to that action. FID assesses how quickly a page becomes interactive and responds to user actions.

Optimal FID values are those below 100 milliseconds. Values between 100 and 300 ms are moderate and values above 300 ms are considered poor.

3. Cumulative Layout Shift (CLS)

Cumulative Layout Shift (CLS) measures the visual instability of a page, i.e. the changes in page layout that occur during page loading. CLS assesses how often page elements shift during loading, which can make it difficult for users to interact with page content.

Good CLS values are those below 0.1. Values between 0.1 and 0.25 are moderate, and values above 0.25 are considered poor.

Why use Google PageSpeed Insights?

Improved position in search results

Page load speed is one of the factors that affect ranking in Google search. Optimised pages are more likely to rank higher in search results, which can lead to more visits and conversions.

Improving user experience

Page speed has a direct impact on user experience. Pages that load faster increase user satisfaction, leading to higher interaction rates and fewer rejections.

Increasing conversions

Page performance affects conversions and therefore the profitability of a website. Better performance can increase sales, newsletter subscriptions or other business goals. By optimising your site with Google PageSpeed Insights, you can see a significant increase in the effectiveness of your marketing efforts.

Practical steps to improve page speed

File compression

Compressing files such as HTML, CSS and JavaScript can significantly reduce the size of data sent to the browser. Tools, such as Gzip, can be used to compress these files before sending them to the user.

Optimising images

Images often make up a large proportion of the data loaded by a website. Optimising images, by reducing their size without losing quality, can significantly speed up page loading. This can be achieved by using various techniques, such as lossy compression, lossless compression or the use of a suitable image format.

Code minimisation

Minimisation involves removing unnecessary spaces, comments and other unnecessary elements from CSS, JavaScript and HTML code. This reduces file size, which speeds up page loading times.

Use of browser caching

Browser caching allows parts of a page to be saved in the user’s browser cache, speeding up page load times on subsequent visits. Setting appropriate expiry headers and caching rules can significantly improve page performance.

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