Resource Loading at the Cutting Edge | Robin Marx | performance.now() 2023

When it comes to loading page resources, Web Developers are truly spoiled these days, with a plethora of mechanisms and protocol features to choose from. From resource hints to fetchpriority, via 103 Early Hints over prerender/prefetch, and from async/defer/module to fetch(), ... the list goes on and on (oh, and did I mention HTTP/3?). However, many of these options are often misunderstood, both in how they should function and how they actually function in the various main browsers.
In this deep-dive session, Robin starts from real-world examples to show how things like prioritization are supposed to work, how especially Chrome has some pretty advanced loading heuristics, how even the excellent WebPageTest can sometimes be misleading, and how to get started debugging this yourself with things like netlog and (*gasp*) wireshark.
You will walk away with a deeper understanding of what happens under the hood, which will allow you to better deal with the various gotchas and quirks present in today's browsers and resource loading features.
Slides: perfnow.nl/_downloads/2023/Re...
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