Critical path optimization
How to accelerate your performance?

par Ludovic Lefebvre, édition 2021

See the video

Often present in various Web optimization tools, the critical path is a concept that is poorly understood or ignored. When does the first rendering of a page occur? How to identify and optimize blockages? These are the questions I want to answer.

To be interested in the critical path is to dive into the functioning of browsers and the construction of the HTML page. To optimize it is to know very different techniques of layout and prioritization on the resources essential to the display of the first pixel. The critical path is the bottleneck of the application.

For this reason, improving the critical path means anticipating many performance problems (FP, LCP, Speed index, FID).

My goal is to present, with concrete and quantified examples, the most efficient techniques I could experiment to reduce the number and size of critical resources: caching policies, js and css minification and prioritization, font management… In addition to the diagnosis, I will talk about the most adapted monitoring tools available on the market.


Ludovic Lefebvre

Presented in French by Ludovic Lefebvre APM Team Leader, Cdiscount

I’m the person who triggers 10,000 requests/second without breaking a sweat, a performance crazy programmer and competitor.

I started the web performance adventure in 2008 at Cdiscount, going from load testing to back end and front end optimization. Today, I’m in charge of the “coaching perf” team and my mission is to bring support and innovative solutions to web issues. In my free time, I am passionate about mind mapping and electronic music composition.