Two years ago, Fasterize conducted a webperf audit for Uni-Médias (Parents, Dossier Familial, Santé Magazine, etc.). In the meantime, Google has integrated Core Web Vitals into its ranking algorithm, the 3 metrics that evaluate the quality of the user experience through loading speed.
In order to push UX and SEO optimizations even further, Mustapha Omar, CTO of Uni-Médias, once again relied on Fasterize’s expertise to apply the recommendations of the speed audit . Feedback, and practical cases of optimization of the famous LCP, CLS and FID, which make up, among other things, Google’s PageSpeed Insights score.
Fasterize: Since your first web performance audit, Core Web Vitals have entered the UX and SEO scene. What has changed for you?
Mustapha Omar : The audit allowed all teams to be involved in the subject of web performance , with the implementation of reporting shared internally with all stakeholders in the digital department. The technical and business teams have an overview and monitoring of loading times, key events in performance developments, and benefit from an alerting system in the event of an incident.
And since then, indeed, Core Web Vitals have come into play. It helped us a lot to have clear KPIs from Google, which indicates a path to follow, the same for everyone. Obviously, we continue to follow the webperf ranking that Fasterize achieves with the JDN, because it remains a benchmark for setting the objectives to be achieved.
In particular, LeMonde.fr and 20minutes.fr are references whose performances we are trying to match: their scores are always good, web performance examples to follow!
Advertising is central to revenue, but like any third-party script, it can degrade speed if poorly implemented. What are the challenges for Uni-Médias, and how do you address them?
MO: I’m probably not telling you anything new when I say that third parties are not inevitable for loading speed. Moreover, as we follow the recommendations of the Fasterize speed audit, our 3 titles whose revenue model is based on advertising have Core Web Vitals in the green (Parents.fr, Santemagazine.fr and Momes.net) and are at the top of the rankings in their respective categories.
Even in the last quarter of the year, our busiest for advertising, all of our sites had good Largest Contentful Paint , Cumulative Layout Shift , and First Input Delay , and that’s still the case.
Are there some Core Web Vitals metrics that are more complicated to optimize than others?
MO: Our challenges have evolved compared to the time when the Speed Index was our only reference. If this metric is included in the calculation of the PageSpeed Insights score , the cards have been reshuffled by Google with the Core Web Vitals, and our challenges have evolved. And indeed, depending on the sectors, some metrics are more complex than others to improve.
Generally speaking, having a good Cumulative Layout Shift for a media site is a real challenge , especially because of the presence of advertising spaces. This score evaluates visual stability, and it does not only take into account the visible part of a page, it is also calculated during scrolling, which makes its optimization even more difficult.
We have put a lot of effort into optimizing our CLS, following Fasterize’s advice which has allowed us to make great progress. On Parents.fr, 90% of pages now have a good CLS score , whereas a little less than a year ago, they were less than 25%.
To go into detail, Parents.fr has experienced the most spectacular performance evolution.
Evolution of the Cumulative Layout Shift (CLS) for the Parents.fr site between 2021 and 2022: nearly 90% of pages have a good CLS in 2022, vs. 24% in 2021
In practice, what have you put in place to optimize your CLS?
MO: For websites that integrate advertising, or more generally third-party content, reserving spaces with the right dimensions is one of the essential best practices for optimizing CLS. Our main optimization axes therefore consisted of:
- reserve fixed spaces for advertising locations, based in particular on statistics for the different formats;
- also reserve fixed spaces for all images ( definition of width / height attributes );
- optimize fonts to minimize shifts due to fallback fonts .
I talked about the impact of advertising on CLS, but you should know that it can also be impacted by first-party content such as text. Indeed, if fonts are loaded after the initial display of the content in a default font or a system font, the space occupied by the text with the final font can change, and therefore cause layout shifts that will degrade the CLS.
And the difficulty doesn’t stop there, because if the LCP element is text content, it still needs to be displayed as quickly as possible… but the entire layout needs to remain stable. Here too, you need to think about reserving a location with the right dimensions! Web performance is really the art of compromise that must be practiced constantly.
Fortunately, there are always solutions. So, to ensure both fast loading and visual stability of our pages, we have implemented lazyloading for third-party content while providing locations with fixed dimensions .
What tools have you implemented to deploy and monitor your web performance following the speed audit?
MO: There are many good tools available today to measure and optimize Core Web Vitals. Here are a few of our favorites:
- the Chrome Web Vitals extension (a must-have),
- Waterfaller.dev – besides screenshots to show improvements, it helps to prepare the user story ready to post in the dev team backlog! ;
- Treo.sh’s Scan option to isolate slower pages;
- Webvitals.dev/cls ;
- WebPageTest – notably with this very practical JavaScript which allows you to analyze the behavior of the page when scrolling , i.e. below the waterline ( described and available here );
- We also use Dareboost for its synthetic monitoring features.
Finally, to share data internally with technical teams, but also marketing, product and SEO, Google Search Console is very telling. All the people who have an impact on the functional aspects, monetization, SEO… can observe the impact of optimizations on a common support.
Google Search Console: evolution of the number of pages considered fast by Google in March 2022, following the integration of front-end optimizations recommended by the Fasterize web performance audit
Google Search Console: Number of pages considered fast by Google in December 2021, before the integration of front-end optimizations recommended by the Fasterize web performance audit
And now, what are your next challenges in terms of web performance?
MO : When you work on loading speed, you can never rest on your laurels. Now that we have good Core Web Vitals, the hardest part is maintaining our positions.
Each change or new feature on a site can degrade the display speed. Keeping a site fast by making it evolve therefore requires constant attention ! We saw it with Dossierfamillal.com for which we needed to do A/B testing : there was an impact on our LCP which was green, and which then exceeded the threshold required by Google to be considered good. But fortunately, with Fasterize’s recommendations, we are doing what is necessary to maintain good performance in relation to our objectives, both for the quality of experience of our users and for our SEO.
Concretely, our next steps are:
- challenge our third-party content providers to optimize Total Blocking Time (editor’s note: TBT, the equivalent of First Input Delay in Google Lab data, which evaluates interactivity and counts for the PageSpeed Insights score) ,
- continue the collaboration with our AB Test provider and identify solutions to find a good Largest Contentful Paint,
- implement a Content Delivery Network (CDN) to reduce our server response time ( TTFB ),
- further improve the CLS of our desktop pages, which have specific issues related to advertising packaging,
- optimize the front-end of other sites in our group.
It is a programme that is both ambitious and stimulating, and we know that we are well supported.
And that’s not all… We are also committed to improving our carbon footprint by monitoring and reducing the environmental impact of our sites, and web performance is one of the best practices for moving towards eco-design .
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