… we discovered that the origin server became infrequently unreachable. Since neither CDN nor origin server were showing any incidents, we initially were confused by these inexplicable periods of Origin unreachability.

Since the beginning, Google has insisted AMP is the best solution for the web’s performance problem. And Google’s used its market dominance to force publishers to adopt the framework, going so far as to suggest that AMP’s the only format you need to publish pages on the web. But we’ve reached a point where AMP may “solve” the web’s performance issues by supercharging the web’s accessibility problem, excluding even more people from accessing the content they deserve.

Using script injection in WebPageTest enables me to experiment, to explore the complexities of which origins to preconnect too and which ones to avoid, and evaluate the results before I get clients to start changing their code.

While a good TTFB doesn’t necessarily mean you will have a fast website, a bad TTFB almost certainly guarantees a slow one.

… la webperf, c’est avant tout de l’UX qui consiste à offrir une expérience de navigation fluide & rapide, afin de faciliter la consultation et l’achat de vos produits/services.

Il serait peut-être temps de se rappeler pourquoi donner trop de pouvoir à l’État est dangereux, pourquoi c’est au citoyen de contrôler son État et pas l’opposé, pourquoi la vie privée et le secret des correspondances sont essentiels à la vie démocratique.

We’ll discover why front-end performance matters, how to measure your web application performance, and what tools you should use to collect these relevant metrics.

stale-while-revalidate helps developers balance between immediacy —loading cached content right away— and freshness —ensuring updates to the cached content are used in the future.

Total Blocking Time is a companion metric to Time to Interactive. For each task, it considers all time except for the first 50ms to be "blocking time". Total Blocking Time is, then, the sum of all the blocking time that fall between FCP and TTI.

Accessibility is a holistic practice, essential to some but useful to all. It is a practice that touches on many aspects of good web design and development, especially performance. This talk will highlight opportunities and techniques to improve your website or web app’s performance by embracing an accessible, inclusive mindset.

Have you ever been reading an article online when something suddenly changes on the page? Without warning, the text moves, and you've lost your place.

If you're using a web font, you're bound to see a flash of unstyled text (or FOUC), between the initial render of your websafe font and the webfont that you've chosen. This usually results in a jarring shift in layout, due to sizing discrepancies between the two fonts. To minimize this discrepancy, you can try to match the fallback font and the intended webfont’s x-heights and widths [1]. This tool helps you do exactly that.

Le travail qui nous attend est énorme. Les changements d’habitude peuvent paraître insurmontables (j’ai passé une semaine chez mes parents, produits des Trente Glorieuses, je saisis pleinement l’ampleur du travail), mais on n’a pas vraiment le choix.

"Eyes don't lie: understanding users' first impressions on website design using eye tracking"

À la question « Combien coûte un site web ? », répondre par un chiffre n’a pas de sens. Pour estimer le coût d’un site web, la solution consister à lister les éléments nécessaires à la conception et à la vie d’un site.

Configuring TLS is perhaps the most complicated and error-prone of all IT tasks, and this tries to make it as easy as possible.

To make this risk-score system work accurately, website administrators are supposed to embed reCaptcha v3 code on all of the pages of their website, not just on forms or log-in pages. Then, reCaptcha learns over time how their website’s users typically act, helping the machine learning algorithm underlying it to generate more accurate risk scores. Because reCaptcha v3 is likely to be on every page of a website,  if you’re signed into your Google account there’s a chance Google is getting data about every single webpage you go to that is embedded with reCaptcha v3—and there many be no visual indication on the site that it’s happening, beyond a small reCaptcha logo hidden in the corner.

Just is a build task definition library. Tasks can be composed, executed in series and in parallel. Logging, command-line arguments, conditionnals, a very simple API…

Google Fonts are easy to implement, but they can have a big impact on your page load times. Let’s explore how we can load them in the most optimal way.

A visual way to understand CSS specificity. Change the selectors or paste in your own.