Cetelem is the main brand of BNP Personal Finance. To be at the top of its market in the Banking-Insurance sector, but also on the Google results page, the user experience must be optimal and all pages of the website fast. Cetelem’s digital teams were already working on loading speed, and to continue to save even more milliseconds, they called on Fasterize for an audit. Meeting with Vincent Heckel, web performance manager.
What are the web performance challenges for a credit site?
Vincent Heckel : Cetelem welcomes 1.5 million visitors each month. We have other well-known brands, such as Cofinoga, Crédit Moderne, etc. whose performance and all user journeys we monitor .
I have been working on the subject of web performance internally for several years because it is essential to have pages that display quickly, so that users can go to the end of the conversion funnel . Moreover, we had already observed that when the display of our pages slowed down, our conversion rates followed the same downward slope. This is a risk that we cannot take, we must have fast pages continuously !
It is also essential to position ourselves in relation to our competitors . As leaders in consumer credit, we have no right to lag behind in terms of user experience, and therefore in terms of SEO. Indeed, speed is one of Google’s ranking criteria , especially since Core Web Vitals are part of its ranking algorithm .
What KPIs do you track for loading speed, and with what monitoring tools?
VH : Initially, I was following the Speed Index , and the availability of the different pages of our users’ journeys.
Dareboost allows us to monitor our web performance, and we also have regular reports and an alert system, especially when the Speed Index or the weight of the pages exceeds a certain threshold, or in case of unavailability. This monitoring allows us to follow what is happening on the front-end and user side, in addition to the monitoring on the back-end and servers provided by the IT teams.
When Google announced the Page Experience update , we also included Core Web Vitals in the metrics to track and optimize, because in addition to the quality of the experience we want to offer our users, SEO is crucial for us. Respecting the thresholds set by Google for LCP , CLS and FID is not an option, it is a necessity! So we set ourselves the goal of going green for these 3 metrics, in other words, being below these thresholds:
- 2.5 seconds of Largest Contentful Paint (LCP)
- 0.1 for Cumulative Layout Shift (CLS),
- 100 ms for First Input Delay (FID).
Google’s recommended performance thresholds for the 3 Core Web Vitals metrics that assess the quality of the user experience
Before carrying out an audit, your teams were already working on loading times. What led you to seek webperf support?
VH : The webperf culture is well established, and we optimize our performance internally. We have the skills and resources to do it, but I’m probably not telling you anything new by saying this: some advanced optimizations are complex to implement . To ensure their ROI and performance gains in relation to the efforts required, an external perspective is useful to know how to prioritize projects .
For the Cetelem site, we had achieved good performance over the course of developments and redesigns , but despite this careful monitoring, we had reached a ceiling and we wanted an expert vision to go even further in improving loading speed, on all our user journeys, for all devices . We knew that we could still progress thanks to this audit, and above all, we wanted precise answers to our issues specific to the world of credit, taking into account our technical and security constraints.
What lessons did you learn from this audit, and what results did you see after implementing the optimizations?
VH : First, we were able to confirm that we were already good on the Speed Index. But we had a lot of room for improvement on the Core Web Vitals, and Fasterize gave us a lot of personalized advice to optimize them.
For example, we gained 55% performance on the CLS by following one of the audit recommendations, about an animation that was triggered by scrolling on one of our screens. It was enough to magnetize the content to improve the stability of the page and respect the thresholds recommended by Google. It was easy to set up, with convincing and immediate results.
In its PageSpeed Insights tool , Google also recommends adopting next-generation image compression formats such as WebP. On our website, we work with external service providers who may integrate content, including images that are not optimized for loading speed, and which can therefore make our pages heavier.
The Fasterize webperf audit was the starting point for a project to optimize all our images to be state-of-the-art, in the most efficient compression formats, including WebP but also AVIF (image compression formats that the Fasterize SaaS solution allows to implement automatically and on the fly for an entire site – editor’s note) .
One of the latest developments we implemented is critical CSS . We have large CSS files, with all the data needed for all pages. I intended to reduce the size of the files, but I knew that there was a potential impact on the display of most of our sites. This is a complex project that the Fasterize audit allowed us to address . We now call a file that contains the critical CSS, and that loads as quickly as possible for our homepage and our key pages. Their display is thus optimized without taking any risk for the other pages of the site. This technique allowed us, in addition to all the optimizations already implemented, to gain another 20% on the Largest Contentful Paint .
How are your teams organized to deploy and monitor the optimizations recommended by our webperf audit?
VH : We work in Agile mode , and all these recommendations are transmitted to the Product Owner with a prioritization of tasks based on their complexity and expected gains .
For the development of new pages and new content, each team is empowered by production implementation procedures, and all pages are evaluated before they are put online. Our site has many different page templates, and to respect our Performance Budget , we had defined, among other things, best practices and a maximum weight for each type of page, and an alert system for a posteriori verification .
The entire life of our sites and pages is part of a real quest for the best optimizations for our loading speed, based on precise advice that meets our business needs. The audit recommendations benefit the front-end of our current site, and we capitalize on them for our redesign project, but also for the other sites in our eco-system.
To conclude, I would add that this audit does not only benefit our site, it is also an opportunity for the teams to develop their knowledge and expertise by being supported by recognized webperf experts !
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