Sacha Morard has been CTO of the Le Monde group since 2018 (Le Monde, Courrier International, Télérama, Huffington Post, L’Obs). Former CTO of Le Parisien, web performance is a subject he has mastered for a long time. For Lemonde.fr, which records 600 million page views per month (up to several billion in 2020), and whose traffic is 60% mobile, how are resources organized to optimize loading speed? With which tools and by following which KPIs? Interview.
How many people make up the technical teams of the Le Monde group, and how do they manage web performance?
Sacha Morard: The digital technical department has 75 members: Developers, Tech Leads, VP Engineering and Product Owners organized into feature teams , who work with UI and UX Designers, Marketing profiles, etc. But there is no team that only does web performance. Performance is central to our entire roadmap – for example, even our Audience division follows the Core Web Vitals , while this could be considered a purely technical or SEO subject. Thus, most teams master the subject of web performance, relying on expert contacts internally.
How did you make web performance a topic for all teams, not just the technical team?
SM: Le Monde has almost a public service mission. Behind the title, there is a promise. Readers are increasingly subscribers, and we must take care of them by offering them a quality user experience , smooth navigation and fast pages. This is why we think about web performance from the beginning of all our projects.
In 2018, we redesigned the Lemonde.fr website to put web performance at the center. In general, major development work is carried out first on Lemonde.fr, and the other titles in the group inherit it. This has become a key issue and I imposed this KPI on everyone: having fast pages and good loading times was a prerequisite before delivering this new version. One of the objectives was to reduce the Speed Index by 60% on mobile in 3G .
We could have turned to Instant article and Google AMP , which were tempting at the time, but I preferred to make the site intrinsically fast, outside of AMP. In the end, we didn’t need to go to this format, and the results were so convincing that web performance is a subject that went up to the Comex, which fully appropriated it. Concretely, the overall work of optimizing the user experience led us to +24% of page views and +46% of subscriptions .
You should know that most of our subscribed audience uses the desktop and that the mobile audience is more volatile. But we are obviously aware of the importance of mobile uses, and especially the importance of having a Mobile First site , especially for our Google SEO.
Moreover, we collect all our webperf metrics on mobile, by simulating browsing on an iPhone 6 in 3G. This is a good way to know if our pages are really fast , even in browsing conditions with a degraded device and network. We also compare ourselves with the performance of our competitors to have a benchmark and situate ourselves in our ecosystem.
To measure your performance, what indicators do you follow? Are Google’s Core Web Vitals a game changer ?
SM: Historically, we closely monitor our Speed Index , our Time To First Byte (especially the handshake ), the weight of the pages, or even the weight of the JavaScript.
We use SpeedCurve’s alerting system to track our Budget performance .
For example, when we put our new Consent Management Platform (CMP) into production, we were able to be immediately notified of the impact on site performance, and we were able to intervene to optimize loading speed.
Furthermore, since Google announced the arrival of Core Web Vitals with the Page Experience update , we have integrated these metrics into our KPIs. In any case, when we optimize Core Web Vitals, the Speed Index follows. And then, being at the top of the JDN webperf ranking is exhilarating, we give ourselves the means to stay there.
In terms of business and marketing KPIs, SEO traffic is an important benchmark . If we deliver a product that is not optimized, and it degrades page speed and user experience, we see it very quickly. It is even a more obvious indicator compared to what we could observe on usual user journeys, because obviously, we never deliver anything that would degrade performance to the point that visitors leave the site.
How do you anticipate peak loads related to current events? They can be colossal!
SM : The advantage of an intrinsically fast site is that it can absorb load peaks much more easily. As for Lemonde.fr, for example when there are elections or official speeches, our site is dynamic, but if necessary we can secure our platform by caching certain pages on our CDN , and we plan a degraded mode in the event of a critical technical incident, as a precaution.
But in practice, even in the event of a very high traffic peak, our site is configured to hold up without any problems. We experienced peaks during the last municipal elections, or during the Covid crisis, where traffic went from 50K visitors in real time to 240K in a few minutes .
What allows us to hold the load, besides the fact that the webperf is processed server-side, is that our entire infrastructure is optimized. Our servers respond on HTML and the assets are on our CDN.
Why did you make this choice? Because if we cached the HTML on a CDN, we would need to maintain two versions of the same page each time: subscriber version and free visitor version. We would then need JavaScript to load the content for subscriber visitors, with a risk of flickering … And that does not correspond to the UX quality standards that we want.
Another technical point that allows us to optimize the loading speed on our sites: AB tests carried out Server side . Thanks to this bias, no more need for JavaScript libraries that could weigh down the pages.
We do First Party personalization with light recommendations , on truly dynamic sites: user session, login , content adapted according to the device (adaptive), display of elements for mobile adapted on the server side… Thus, like all the major players in the market, our infrastructure allows us to guarantee the scalability and dynamism of our sites, and especially their performance and loading times. We do everything to ensure that our features and content are accessible to our users without degrading speed, by playing on elasticity.
On a daily basis, what are the optimizations whose effects on loading speed do you measure the most?
SM: The optimizations that had the biggest impact on our page loading speed are:
- Reducing the weight of pages : for reasons of SEO constraints, we did not want to move towards Single Page Apps (SPA), which may seem contradictory compared to our frameworks . The site is dynamic, the HTML and JavaScript layers are lightened, and customization can then be done without slowing down the pages.
- Image optimization : we had developed an image server to handle WebP formats , but the degradation was such that it was taking us away from our user experience goals. Since the image quality didn’t seem satisfactory to us, we finally abandoned WebP, and there is inevitably an impact on bandwidth. In the end, we are very successful in adapting the size of images according to screens, and in compressing them correctly in JPEG, and everyone benefits on both sides of the browser, especially on the quality of the visuals.
- Critical CSS : This is a technique that is very useful to us, especially for the first page where the CSS is loaded inline . However, you should know that this technique is difficult to implement on a site that is not dynamic. The principle is quite simple, but complex to implement. During the first visit, a piece of CSS (the critical ) must be written inline directly in the HTML, while the rest of the style sheets must be loaded asynchronously. For us, this critical CSS is previously calculated by a bot that selects the CSS rules useful for rendering the visible part of the page, and this calculation is done for each type of device .
Also, as I said earlier, the HTML of our pages is served by our servers, and this is how we can apply all these techniques, which would be more difficult with a CDN.
And Third Parties? On a press site, advertising is vital, but it also has weight.
SM: Managing Third Parties could have been complex, but that is no longer the case. Le Monde is a high-traffic site with a general information mission, so of course, there is advertising. You have to know how to make some compromises. To optimize our performance, we have isolated the advertising part from the rest of the site, which means that it has less impact on the loading speed of the pages – Speed Index and Cumulative Layout Shift (CLS), in particular. Thanks to this dissociation between editorial content and advertising content, if an ad loads slowly, the space is reserved anyway, and the impression of slowness does not affect the page as a whole, only the ad, if applicable.
Advertising is a case among all third parties, generally speaking, we pay attention to everything we integrate on our pages. We have also chosen not to have a tag manager to avoid integrating content that we would not control. There is only one left on our subscription tunnel that we are changing.
Finally, what advice could you give to teams who want to start optimizing the performance of their website?
SM: I would say that one of the important points for leading a web performance optimization project is to succeed in evangelizing the teams internally . Very often, the subject speaks to some of the teams, and they pass the buck, without realizing that the whole business is at stake . That is exactly what you have to succeed in demonstrating!
And in this case, to install this culture, nothing beats an expert who comes to explain what webperf is and what it can bring.
Then we need internal ambassadors, and we need to anchor performance in the roadmap , otherwise it will fall by the wayside. In other words, the subject must be protected .
To this end, the Performance Budget is a necessary safeguard. Personally, if I have to refuse the addition of a third-party script, I can easily explain why: I test and show the impact on loading speed, with Lighthouse , PageSpeed Insights or WebPageTest scores to support it.
There is no shortage of measurement tools, indicators, and techniques for optimizing the user experience, and whether internally or using optimization solutions , Technical, SEO, Marketing, Product teams, etc. Everyone benefits from the tangible benefits of fast web pages.
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