3 August 2026

Web Performance Audit: The Importance of Monitoring Your Website’s Pages

Whether as part of a complete website redesign, the implementation of a new feature, or ongoing maintenance and enhancement, page load time is now a key metric to monitor and track after each deployment to ensure it meets current standards set by free or paid speed-testing tools and, above all, the expectations of users—particularly those on mobile devices.

According to data provided by Google:

– A 0.1-second load time can result in an 8% increase in conversions
53% of mobile users leave a page if it takes more than 3 seconds to load
77% of smartphone users are more likely to make a purchase from a company if its website or mobile app allows them to complete the purchase quickly.

A few tenths of a second added to your load time unfortunately means you’ll lose conversion points—and thus revenue—but it will also have a negative impact on your organic search engine optimization (SEO) and even on your paid search advertising (SEA) through the Quality Score.

It is therefore essential to consistently prioritize your page load times in order to:

Offer the best user experience to your prospects and customers to increase the length of their visits and the number of page views
Increase your conversion rate to generate more leads and revenue
Optimize your organic search rankings, as page load time is one of the criteria used by Google’s algorithm

Since 2020, Google has become the leader in this field by defining key performance metrics (Core Web Vitals) for websites to evaluate their loading speed and user experience. Google has thus made free tools available (Search Console, Google Lighthouse, Page Speed Index) to test and monitor these key performance indicators.

What are the top 3 Core Web Vitals to monitor?

Largest Contentful Paint (LCP)

It refers to the time it takes for the browser to display the largest visible element in the viewport from the moment the user attempts to access the URL.

The LCP applies only to the main content located above the fold. This includes images, videos, or blocks of text that are visible without the user having to scroll.

First Input Delay (FID) / Interaction Next Page (INP)

This is the time between when the user first interacts with the displayed page and when the browser responds to that interaction. This calculation therefore quantifies the user’s experience.

A low FID ensures fast load times and responsiveness, and thus a positive overall experience. FID will be replaced by INP in 2024, which evaluates the overall responsiveness of all interactions on a web page, rather than just the first one. This provides a more consistent overall assessment.

A good INP corresponds to a value of 200 ms or less (100 ms for the FID).

Cumulative Layout Shift (CLS)

The CLS calculates the total sum of the scores for each layout shift that occurs during page load and throughout the page’s lifetime.

The misalignment of elements prevents users from interacting properly, thereby affecting the user experience.

Time to First Byte (TTFB)

This metric measures the time between a request for a resource and the moment the first byte of a response begins to arrive.

Since TTFB occurs before user-centric metrics such as First Contentful Paint (FCP) and Largest Contentful Paint (LCP), it is recommended that your server respond to browser requests quickly enough so as not to negatively impact their scores.

As a general guideline, most websites should aim for a TTFB of less than 0.8 seconds.

First Contentful Paint (FCP)

It measures the time elapsed between the start of page loading and the moment when some of the page’s content is displayed on the screen.

For a good user experience, your site should have a First Contentful Paint of less than 1.8 seconds.

Google tools provide a good overview, but they only reflect user results at a given moment. Using other tools such as NewRelic, GTMetrix, and WebPage Test, among others, allows for continuous analysis of a website—or real-time analysis—taking into account deployments and traffic spikes.

Performance analysis must also be tailored to the specific context, technologies, and CMS used. For example, the analysis will differ between WordPress, Adobe Commerce, and a CMS used with a headless front end versus a front end powered by the solution itself.

First and foremost, it is necessary to set measurable and quantifiable goals for improving web performance KPIs.

Some best practices to follow

Measuring oneself against competitors

These tools also let you compare your website’s performance with that of your competitors. It’s always helpful to benchmark yourself against others. After all, simply being “in the green” may not be enough if your competitors are outperforming you.

Key front-end technical considerations

HTML code quality: the number of elements in the DOM, the use of appropriate tags, filled-in attributes, etc.
Cascading Style Sheets (CSS): compression, caching, versioning, CDN, level/targeting…
JavaScript: compression, caching, versioning, CDN, file size, number of requests, multiple calls, loading third-party scripts, deferring certain loads, fixing errors that slow down loading (even if they aren’t blocking) …
And assets (content, media, etc.) : image compression, use of a CDN, use of next-generation formats, implementation of lazy loading, adapting loaded fonts to usage (by adjusting the number of glyphs), adapting loaded images based on resolution…

The key metrics to analyze as part of back-end performance monitoring are as follows:

Database performance: Since data is processed and retrieved from the database, it is important to ensure that queries execute as quickly and reliably as possible. It may sometimes be helpful to add indexes or optimize certain queries in order to achieve faster response times and improve overall application performance as well as the platform’s ability to handle load (scalability).
Server load time: This is the time it takes for your server to respond to a request and return the page to the user. The shorter it is, the better. After optimizing the database, it may be helpful to improve the existing caching system to make it more efficient and thus drastically reduce page load times. To do this, you need to adjust the cache granularity and its expiration time, and verify its effectiveness…
The server error rate : Some pages that are accessed generate errors. The goal is to minimize errors as much as possible. Errors reported to the application result in longer load times because the error itself must be handled, and writing logs generates unnecessary disk I/O, which in turn increases the load.

Always keep in mind that performance optimization begins during the technical design phase, when mockups are created and navigation paths are designed. During the integration phase, developers must therefore be trained in best practices.

In light of the goals you’ve set, it’s essential to strike a balance between optimizing your customers’ user experience and stubbornly trying to conform to a model designed to satisfy Google’s algorithm—a model whose content and updates no one fully understands.