This is where another Sentry feature comes into play. After you’ve signed up and configured everything, head to the Performance section and you’ll see which transactions are getting better over time and which have regressed, or gotten slower

We’ve seen how the “feel” of a site can affect the business, but what does all of that tell us about how to build our sites?

• How fast should we be to reduce frustration?
• What should we be considering in our performance budgets?
• How do we leave our users feeling happy?
• I think these may be secondary questions…

A better question to start with, is:
Will adding a new feature delight or frustrate the user?

En rythme de croisière, et grâce à une stratégie de cache plutôt défensive, 3 machines standard (8 vCPU et 30 Go de RAM) sous Node sont suffisantes pour supporter la charge. Ce dimensionnement est auto-scalable en cas de très fort pic de trafic, c’est-à-dire que le nombre de machines augmentera automatiquement pour absorber l’afflux de connexion. De quoi envisager plus sereinement les grandes soirées de matchs.

If you’re using anti-flicker snippets as part of your experimentation toolset, you should measure how long visitors are being shown a blank screen, with the aim of reducing the timeout values or even removing the anti-flicker snippet completely.

Not having to use a JavaScript framework also meant that HTML, not JSX or Vue components, is now front and center in the code you write. This helped me avoid the usual traps when writing React: the infamous div soup, inaccessible components, or non-semantic tags.

A couple of years ago, my first few days on a new web performance project were always slow going. […] In a bid to address this, I introduced a new tool into my arsenal so that I could hit the ground running much faster, and get answers to my clients much sooner.

Extended Validation certificates are expensive and degrade performance. Move to an OV certificate if you can!

In this case, we were given expectations of what content would be displayed and where, and those expectations ended up being misleading. We now have to re-orient ourselves to where the content ends up being displayed.

When the skeleton screen doesn’t match the outcome, we’ve created confusion and frustration that will overcome any benefit you might have gotten from trying to handle that delay in a better way.

1. Build for mobile first
2. Stop using carousels and sliders
3. Optimize your images
4. Lazy load images
5. Load web fonts with font swapping
6. Create smooth animations
7. Minimize third-party impact
8. Preconnect to key third-party domains
9. Wrangle your apps
10. Monitor the number of requests per subdomain

There are two reasons why people use CSS grid:

• 😎 CSS is awesome! It's a fact, deal with it.
• 🛠️ Grid is a great tool to build complex two-dimensional layouts.

I sometimes have a third reason to use CSS grid: prevent layout shifts.

We intuitively know that faster is better, but what's the psychology and physiology behind it?

I recommend the part on how to curb the JS tax (14:48).

Blurhash strings are short enough to be added as a field in a JSON object and to be stored in a database. The implementations are small and easy to port to new languages, and the end result is a smooth and interesting experience for your users.

Slowfil.es generates URLs for slow ressources

Je suis convaincu que la formation dans les technologies Web de base souffre de lacunes évidentes qui ont conduit à cet état des choses. Cette connaissance essentielle d’HTTP, HTML et CSS fait défaut. Or la réponse à cet engorgement réside dans ce savoir… Il est la clef pour apprendre à se passer de JavaScript.

It is great to see Google create a new Page Experience signal using a brilliant object-oriented approach. I think it is smart, flexible, and scalable. That said, in my opinion, the signal must have teeth in order for it to be taken seriously by site owners, developers, and SEOs. If not, it can fall by the wayside.

A great way to get a RUM overview of a page’s performance, at low cost, very quickly.

We need an alternative to JPEG that a) is widely supported, b) has better compression efficiency and c) has a wider feature set. We believe AV1 Image File Format (AVIF) has the potential. Using the framework we have open sourced, AVIF compression efficiency can be seen at work and compared against a whole range of image codecs that came before it.

Being able to run Google’s Lighthouse analysis suite programmatically provides a lot of advantages, especially for larger or more complex web applications. Using Lighthouse programmatically allows engineers to set up quality monitoring for sites that need more customization than straightforward applications of Lighthouse (such as Lighthouse CI) allow.

JavaScript is your behavior layer; the way to add interactivity to your sites, to provide a slick and delightful user experience, to make everything fast and easy and clean. But at some point everything changed: the tail started to wag the dog instead and development became Javascript-first. We'll talk about how you maybe shouldn't rely on JS as much as you're told to, and some practical strategies for how to build sites without reaching for a JS framework as first, last, and only tool for making the web happen.