All times are on Central European Time (CET).

Conférences de We Love Speed 2019, le 20 septembre
Time Exploration AuditoriumDeep-Dive Auditorium
09:00 Attendees’ welcome
09:25 Conference Opening

Browser 101: how the browser loads a page

in French by Estelle Weyl
25 minutes + questionsExploration Auditorium

To understand Web Performance, developers must first understand how a browser works. Let’s discuss what happens when a user requests a page and how the browser loads the page.

Why does frontend performance matter?

by Matt Hobbs
25 minutes + questionsDeep-Dive Auditorium

A talk giving my opinion on why frontend performance matters and it’s huge impact on users from the perspective of government services. The talk focuses on the UK central government’s website, [GOV.UK]( It contains details on the history of Government…

10:05 Change of room

How to link performance and ecology?

in French by Romuald Priol
45 minutes + questionsExploration Auditorium

The Web must be fast, optimized and efficient. But achieving a high-performance website is not easy when you consider the ecological aspects of the resulting code or the additional servers on your infrastructure. Web Performance is not Green, but it…

Responsible JavaScript

by Jeremy Wagner
45 minutes + questionsDeep-Dive Auditorium

While the performance of JavaScript engines in browsers have seen continued improvement, the amount of JavaScript we serve increases unabated. We need to use JavaScript more responsibly, which means we must rely on native browser features where prudent, use HTML…

11:05 Coffee Break
11:30 Conferences resume

How PagesJaunes climb into the top 10 of the webperf ranking in France

in French by Loïc Troquet
25 minutes + questionsExploration Auditorium

This feedback chronologically retraces all the work done by my team over the past year to improve the webperf on I will review everything that has been implemented, the achievements but also the failures.

Image at scale

in French by Anthony Barré
25 minutes + questionsDeep-Dive Auditorium

Compressing an image is already difficult, and doing it on large volumes and at a lower cost is a real challenge. Together we will see the main principles of optimization and the techniques that result from it: resizing according to…

12:10 Change of room

Keeping Wikipedia Fast

by Peter Hedenskog
45 minutes + questionsExploration Auditorium

The performance team at the Wikimedia Foundation is responsible for measuring the performance of Wikipedia. That is easy right? Setup monitoring and you are ready to go? In theory it is easy, but in practice we have had some problems….

How to make sense of real user metrics

in French by Gilles Dubuc
45 minutes + questionsDeep-Dive Auditorium

Thanks to client-side APIs like NavigationTiming, we can collect a lot of information about the real performance experienced by users. However, the organic nature of this data introduces many pitfalls when it comes to interpreting them. We will look at…

13:10 Launch Break (90 min)
14:40 Conferences resume

HTTP/3: it’s a transport issue!

in French by Benoit Jacquemont
35 minutes + questionsExploration Auditorium

HTTP or Hyper Text Transfer Protocol is the Web protocol. The announcement of HTTP/3 in early November 2018 surprised many people: the time gap between HTTP/3 and HTTP/2 was less than 4 years, whereas 18 years had passed between HTTP/1.1…

Chaperones and curfews: minimising 3rd party impact

by Ryan Townsend
45 minutes + questionsDeep-Dive Auditorium

Every year websites get heavier – but the majority of growth isn’t coming from code written at the organisations running them… it’s coming from 3rd parties. Long gone are the days when it was viable to build everything internally, but…

⚠️ NO change of room between the talks

Feedback on 4 years of XP using a Synthetic Monitoring tool at SeLoger

in French by Antonio Gomes Rodrigues
35 minutes + questionsExploration Auditorium

A few years ago, SeLoger invested heavily in the application performance of its websites. This resulted in jobs creation, the tools purchasing and the creation of an custom-made Synthetic Monitoring solution based on WebPageTest. Today we have migrated to a…

Progressive Web App & Performance

in French by Raphaël Dardeau
25 minutes + questionsDeep-Dive Auditorium

2 years ago, L’Équipe was one of the first in France to launch a Progressive Web App for its mobile website. The web performance earnings led us to fully revamp the desktop version also based on PWA. I’ll share feedback…

16:15 Coffee Break
16:40 Conferences resume

Webperf optimization project: what are we getting into?

in French by Quentin Mathieu, Mathilde Lassort
25 minutes + questionsExploration Auditorium

Do you want to launch or are you in the process of launching a Web Performance optimization project? Let’s discuss together the different stages of maturation of a webperf project in a company through the feedback of, but also…

Honey, I Shrunk the JS Bundles

in French by Antoine Kahn-Dubois
25 minutes + questionsDeep-Dive Auditorium

Working on a web applications for the advisors of a large bank, we faced performance problems caused by the large quantity of JavaScript we were sending our users. We managed to reduce the load time of our app from 9…

17:20 Change of room

Reduce the weight of a mail client UI via CSS / SVG

in French by Nicolas Hoffmann
25 minutes + questionsExploration Auditorium

I’m currently working on the v4 of ProtonMail. The present version is not always easy to operate: the technical debt is inevitable (and performance debt as well), so are heavy CSS and lack of consistency… Revamping is an ideal opportunity…

UX vs DX

by Estelle Weyl
25 minutes + questionsDeep-Dive Auditorium

Fast to code. Fast to show. It doesn’t have to be an either/or situation. All sites should be fast to load, responsive, internationalizable, secure, and performant. It makes sense to use all available tools to quickly implement features, but some…

18:00 Let’s meet in the Exploration Auditorium
18:05 We Love Speed 2019 Ending
18:20 That’s all folks!