Pour éviter l’effet de flickering, l’internaute voit une page blanche en attendant que la page définie dans le cadre du test A/B s’exécute et s’affiche. Autrement dit, l’affichage est volontairement ralenti pour éviter de servir une première version de page qui disparaîtrait pour laisser place à celle qui doit s’afficher pour le test.

Let’s take a look at all of the different Resource Hints we have available to us, real-world examples of how best to use them, and learn about some of the more obscure intricacies and gotchas that we need to be aware of if we want to really get the best out of them (and to make sure that we really are being smarter than the browser).

We believe that data from inactive tabs should be considered unnecessary and distorting the picture.

Interesting take, even if I find it ambiguous to use "FirstMeaningfulPaint" for a Custom Metric. The issue with data from inactive tabs once again highlight that one should always back up their RUM findings with Synthetic Monitoring.

Early Flush the HTTP response, for faster head interpretation

Preloading and prefetching to optimize Instagram feed performance

DOM reflow or layout thrashing should always be kept at a minimum in order to increase performance and provide a fluid, nonblocking user experience.

Stop using cookieless domains, start migrating to HTTP/2!

For 27 years, JPEG has been the workhorse image format. While universally adopted, it doesn’t address many modern use cases including high dynamic range (HDR), transparency, responsive web, lossless and others.

We now track a Page Performance Score based off of four user-centric metrics: (TT)FCP, (TT)FMP, FID, and TBT.

Webpages can be good citizens of battery life. It’s important to measure the battery impact in Web Inspector and drive those costs down. Doing so improves the user experience and battery life.

[Apart from 2 very specific cases where treatments needed to be done without the user request] I have seen exactly zero other instances where Web Workers would have improved the user experience.

Cumulative Layout Shift (CLS) is a relatively new metric to help you understand the delightfulness of the user experience.

This way all the users will have to download upfront is the cover image, which seems pretty reasonable to me.

Predicting what our users will do next is difficult, and it certainly requires a lot of planning and testing. But, the performance benefits are definitely worth chasing.

Adding rel=preconnect to a <link> informs the browser that your page intends to establish a connection to another domain, and that you'd like the process to start as soon as possible.

The Embedded Image Preview (EIP) technique introduced in this article allows us to load preview images during lazy loading using progressive JPEGs, Ajax and HTTP range requests without having to transfer additional data.

Cet article a pour but d’expliquer comment exposer, sans danger, votre API sur le web… et par conséquent à votre entreprise ! Sans oublier les deux objectifs d’une stratégie de sécurisation d’application : mener la vie dure aux attaquants potentiels, tout en facilitant la vie des consommateurs légitimes.

le Synthetic Monitoring présente l’avantage d’offrir une stabilité que les données organiques n’ont pas, donc on en aura toujours besoin. C’est un moyen très efficace de détecter des changements dans la performance qui viennent de nous et non pas de l’environnement. Ces métriques sont toujours utiles sur du très long terme.

Site speed is a competitive advantage that directly influences your conversion rates.

The tools to make our websites fast and accessible are here but we’re not using them. And that’s what makes me mad […] it’s not just bad software design and development if a website is slow. Performance and accessibility aren’t features that can linger at the bottom of a Jira board to be considered later when it’s convenient.