Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
@jpvincent.bsky.social
Webperf expert (audit, trainings, code), Green IT specialist (trainer, audit)
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
#JavaScript: When it comes to breaking up long tasks, the scheduler API seems quite convenient:
await scheduler.yield();
Alas, not supported by Safari yet: caniuse.com/mdn-api_sche...
Thankfully, providing your own fallback implementation is easy: web.dev/articles/opt...
await scheduler.yield();
Alas, not supported by Safari yet: caniuse.com/mdn-api_sche...
Thankfully, providing your own fallback implementation is easy: web.dev/articles/opt...
Scheduler API: yield | Can I use... Support tables for HTML5, CSS3, etc
caniuse.com
October 16, 2025 at 3:48 PM
#JavaScript: When it comes to breaking up long tasks, the scheduler API seems quite convenient:
await scheduler.yield();
Alas, not supported by Safari yet: caniuse.com/mdn-api_sche...
Thankfully, providing your own fallback implementation is easy: web.dev/articles/opt...
await scheduler.yield();
Alas, not supported by Safari yet: caniuse.com/mdn-api_sche...
Thankfully, providing your own fallback implementation is easy: web.dev/articles/opt...
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
I co-wrote a post on the Etsy engineering blog about implementing Speculation Rules API (SRA) to prefetch product listing pages from search results. And many thanks to @tunetheweb.com and @cdaveross.bsky.social for the help and support!
www.etsy.com/codeascraft/...
www.etsy.com/codeascraft/...
www.etsy.com
October 29, 2025 at 5:37 PM
I co-wrote a post on the Etsy engineering blog about implementing Speculation Rules API (SRA) to prefetch product listing pages from search results. And many thanks to @tunetheweb.com and @cdaveross.bsky.social for the help and support!
www.etsy.com/codeascraft/...
www.etsy.com/codeascraft/...
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
C’est officiel, nous avons dépassé la 7e limite planétaire, celle de l’acidification des océans.
Vous ne lirez rien de plus important aujourd'hui. A partager massivement !
bonpote.com/la-7e-limite...
Vous ne lirez rien de plus important aujourd'hui. A partager massivement !
bonpote.com/la-7e-limite...
La 7e limite planétaire est officiellement dépassée : l'acidification des océans
C'est officiel, nous avons dépassé la 7e limite planétaire, celle de l'acidification des océans. C'était attendu par le
bonpote.com
September 24, 2025 at 4:00 PM
C’est officiel, nous avons dépassé la 7e limite planétaire, celle de l’acidification des océans.
Vous ne lirez rien de plus important aujourd'hui. A partager massivement !
bonpote.com/la-7e-limite...
Vous ne lirez rien de plus important aujourd'hui. A partager massivement !
bonpote.com/la-7e-limite...
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
🤔 Why do browsers throttle JavaScript timers?
Why do browsers throttle JavaScript timers?
Even if you’ve been doing JavaScript for a while, you might be surprised to learn that setTimeout(0) is not really setTimeout(0). Instead, it could run 4 milliseconds later: Nearly a decade a…
nolanlawson.com
September 1, 2025 at 6:47 AM
🤔 Why do browsers throttle JavaScript timers?
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
> Peak CPU performance was probably hit in 2017.
With that perspective, you start... (ahem)... "rethinking best practices".
@infrequently.org's @jsnation.gitnation.org talk is pretty worthwhile and digs into the CPU limitations of the main thread.
gitnation.com/contents/pro...
With that perspective, you start... (ahem)... "rethinking best practices".
@infrequently.org's @jsnation.gitnation.org talk is pretty worthwhile and digs into the CPU limitations of the main thread.
gitnation.com/contents/pro...
Frontend’s Lost Decade and the Performance Inequality Gap by Alex Russell
Alex Russell's journey from engineering to product management, the focus on improving web experiences, and optimizing software for end-user success. Considerations include device performance, web dive...
gitnation.com
July 3, 2025 at 9:05 PM
> Peak CPU performance was probably hit in 2017.
With that perspective, you start... (ahem)... "rethinking best practices".
@infrequently.org's @jsnation.gitnation.org talk is pretty worthwhile and digs into the CPU limitations of the main thread.
gitnation.com/contents/pro...
With that perspective, you start... (ahem)... "rethinking best practices".
@infrequently.org's @jsnation.gitnation.org talk is pretty worthwhile and digs into the CPU limitations of the main thread.
gitnation.com/contents/pro...
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
New blog post about #CSS masonry layout, the (fairly) new Item Flow proposal, maybe subsuming multicol, and a light tingling from my Web-Sense. That last part isn’t NSFW, I promise. (Sorry, @brucel.bsky.social.) meyerweb.com/eric/thought...
Masonry, Item Flow, and… GULP?
Masonry layout is a difficult thing to do with CSS at present. Item Flow could make it easy.
meyerweb.com
May 21, 2025 at 8:34 PM
New blog post about #CSS masonry layout, the (fairly) new Item Flow proposal, maybe subsuming multicol, and a light tingling from my Web-Sense. That last part isn’t NSFW, I promise. (Sorry, @brucel.bsky.social.) meyerweb.com/eric/thought...
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
During the keynote of @vueconf.us, @danielroe.dev releases `fontless` - a @vite.dev plugin to apply "magical plug-and-play font optimization".
Created in collab with the @qwik.dev team
This is basically the @nuxt.com fonts module, but for all Vite-based apps 🤯
Created in collab with the @qwik.dev team
This is basically the @nuxt.com fonts module, but for all Vite-based apps 🤯
May 21, 2025 at 1:36 PM
During the keynote of @vueconf.us, @danielroe.dev releases `fontless` - a @vite.dev plugin to apply "magical plug-and-play font optimization".
Created in collab with the @qwik.dev team
This is basically the @nuxt.com fonts module, but for all Vite-based apps 🤯
Created in collab with the @qwik.dev team
This is basically the @nuxt.com fonts module, but for all Vite-based apps 🤯
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
Finally, a LoAF explainer I understand!
The LoAF API is a leap forward for RUM. It lets us find and fix the third parties and other JS that hurts #pagespeed and #UX. The catch? It's tricky to understand. But no longer, thanks to this piece by @andydavies.me!
www.speedcurve.com/blog/guide-l...
The LoAF API is a leap forward for RUM. It lets us find and fix the third parties and other JS that hurts #pagespeed and #UX. The catch? It's tricky to understand. But no longer, thanks to this piece by @andydavies.me!
www.speedcurve.com/blog/guide-l...
SpeedCurve | The Definitive Guide to Long Animation Frames (LoAF)
LoAF lets you identify problem scripts, quantify the impact of third-party scripts, and improve the user experience. Here's everything you need to know to get started.
www.speedcurve.com
May 21, 2025 at 7:09 PM
Finally, a LoAF explainer I understand!
The LoAF API is a leap forward for RUM. It lets us find and fix the third parties and other JS that hurts #pagespeed and #UX. The catch? It's tricky to understand. But no longer, thanks to this piece by @andydavies.me!
www.speedcurve.com/blog/guide-l...
The LoAF API is a leap forward for RUM. It lets us find and fix the third parties and other JS that hurts #pagespeed and #UX. The catch? It's tricky to understand. But no longer, thanks to this piece by @andydavies.me!
www.speedcurve.com/blog/guide-l...
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
📧 Impact environnemental de l'email : dépasser les sujets d'optimisation technique.
Pour le service mail d'Iroco, David Ekchajzer, Bruno Thomas et Adeline Agut, ont réalisé une analyse des gains environnementaux potentiels de plusieurs leviers d'éco-conception.
www.youtube.com/watch?v=RNxz...
Pour le service mail d'Iroco, David Ekchajzer, Bruno Thomas et Adeline Agut, ont réalisé une analyse des gains environnementaux potentiels de plusieurs leviers d'éco-conception.
www.youtube.com/watch?v=RNxz...
Encore une étude sur l'email dépasser les sujets d'optimisation technique
Encore une étude sur l'email : dépasser les sujets d'optimisation technique avec une approche attributionnel & conséquentielDavid Ekchajzer, Eric Fourboul, A...
www.youtube.com
March 28, 2025 at 12:59 PM
📧 Impact environnemental de l'email : dépasser les sujets d'optimisation technique.
Pour le service mail d'Iroco, David Ekchajzer, Bruno Thomas et Adeline Agut, ont réalisé une analyse des gains environnementaux potentiels de plusieurs leviers d'éco-conception.
www.youtube.com/watch?v=RNxz...
Pour le service mail d'Iroco, David Ekchajzer, Bruno Thomas et Adeline Agut, ont réalisé une analyse des gains environnementaux potentiels de plusieurs leviers d'éco-conception.
www.youtube.com/watch?v=RNxz...
Quelques infos sur le comportement des français vis-à-vis de leur téléphone dont l'obsolescence est visiblement programmée
limitesnumeriques.fr/travaux-prod...
limitesnumeriques.fr/travaux-prod...
CP | Limites numériques
limitesnumeriques.fr
March 17, 2025 at 11:34 AM
Quelques infos sur le comportement des français vis-à-vis de leur téléphone dont l'obsolescence est visiblement programmée
limitesnumeriques.fr/travaux-prod...
limitesnumeriques.fr/travaux-prod...
La dernière étude GreenIT sur l'impact global du numérique est sortie : greenit.eco/wp-content/u....
Un petit chiffre : le numérique pour un individu connecté c'est déjà 40% de son budget GES dit "soutenable" (on se limite à 1,5° d'augmentation de la T° globale). Après il faut qu'il mange …
Un petit chiffre : le numérique pour un individu connecté c'est déjà 40% de son budget GES dit "soutenable" (on se limite à 1,5° d'augmentation de la T° globale). Après il faut qu'il mange …
greenit.eco
February 5, 2025 at 11:00 AM
La dernière étude GreenIT sur l'impact global du numérique est sortie : greenit.eco/wp-content/u....
Un petit chiffre : le numérique pour un individu connecté c'est déjà 40% de son budget GES dit "soutenable" (on se limite à 1,5° d'augmentation de la T° globale). Après il faut qu'il mange …
Un petit chiffre : le numérique pour un individu connecté c'est déjà 40% de son budget GES dit "soutenable" (on se limite à 1,5° d'augmentation de la T° globale). Après il faut qu'il mange …
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
Tip to prevent videos from impacting page load:
- Set a low-quality poster image with the `poster` attribute
- Set `preload="none"` (only works if there's a poster)
The latter tells the browser to avoid downloading the video file until the user requests playback.
- Set a low-quality poster image with the `poster` attribute
- Set `preload="none"` (only works if there's a poster)
The latter tells the browser to avoid downloading the video file until the user requests playback.
January 30, 2025 at 3:20 PM
Tip to prevent videos from impacting page load:
- Set a low-quality poster image with the `poster` attribute
- Set `preload="none"` (only works if there's a poster)
The latter tells the browser to avoid downloading the video file until the user requests playback.
- Set a low-quality poster image with the `poster` attribute
- Set `preload="none"` (only works if there's a poster)
The latter tells the browser to avoid downloading the video file until the user requests playback.
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
C'est un événement qui n'arrive que deux fois par décennie : une nouvelle étude de l'Association Green IT sur l'impact du numérique mondial !
Rejoignez nous le mardi 4 février à 17h.
Pour vous inscrire, c’est par ici : t.ly/ptcagtw25
Rejoignez nous le mardi 4 février à 17h.
Pour vous inscrire, c’est par ici : t.ly/ptcagtw25
Nouvelle étude Green IT 2025 Monde sur les impacts du numérique | Planet Tech Care
L'association Green IT publie le 4 février sa toute dernière mise à jour des impacts environnementaux du numérique au niveau monde : IA, objets connectés, TV, smartphones, ... Venez découvrir dès l...
t.ly
January 31, 2025 at 8:21 AM
C'est un événement qui n'arrive que deux fois par décennie : une nouvelle étude de l'Association Green IT sur l'impact du numérique mondial !
Rejoignez nous le mardi 4 février à 17h.
Pour vous inscrire, c’est par ici : t.ly/ptcagtw25
Rejoignez nous le mardi 4 février à 17h.
Pour vous inscrire, c’est par ici : t.ly/ptcagtw25
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
Frontend has been lost in delusions about the relative costs of client-side resources. But the facts are stubborn: smartphone ASPs only broke $350 worldwide for the first time in 2024. That's lower than any i-Device sells for.
The "I" in iPhone stands for "inequality".
The "I" in iPhone stands for "inequality".
January 30, 2025 at 8:56 AM
Frontend has been lost in delusions about the relative costs of client-side resources. But the facts are stubborn: smartphone ASPs only broke $350 worldwide for the first time in 2024. That's lower than any i-Device sells for.
The "I" in iPhone stands for "inequality".
The "I" in iPhone stands for "inequality".
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
🏭 Datacenters, Cloud : comment mieux évaluer leur empreinte environnementale ? Quelles perspectives ? Quelles normes et réglementations ?
https://buff.ly/3WnoDcV
Merci à Rémy Marrone pour cette interview.
https://buff.ly/3WnoDcV
Merci à Rémy Marrone pour cette interview.
Le Média GreenTech Forum | #37 Datacenters, Cloud : comment mieux évaluer leur empreinte environnementale ?
Quel empreinte environnementale pour le Cloud ? Nombreuses sont les organisations à se poser la question et à rester bien souvent sans réponse. Une situation peu confortable alors que les exigences…
buff.ly
January 16, 2025 at 3:59 PM
🏭 Datacenters, Cloud : comment mieux évaluer leur empreinte environnementale ? Quelles perspectives ? Quelles normes et réglementations ?
https://buff.ly/3WnoDcV
Merci à Rémy Marrone pour cette interview.
https://buff.ly/3WnoDcV
Merci à Rémy Marrone pour cette interview.
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
www.highperformancewebfonts.com/read/testing... is the first article on the newly "designed" HPWS resource
High-Performance Web Fonts
Tools and resources on how to use web fonts without sacrificing page loading speeds
www.highperformancewebfonts.com
January 15, 2025 at 9:25 AM
www.highperformancewebfonts.com/read/testing... is the first article on the newly "designed" HPWS resource
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
It's long past time we had a standard way to load CSS asynchronously. link[async] should work just like the tried and true print-media hack, but without the major downside of javascript reliance for applying CSS.
Join me with a plus one here? github.com/whatwg/html/...
Join me with a plus one here? github.com/whatwg/html/...
Async css · Issue #3983 · whatwg/html
Allow css files to be marked as async meaning that they will not block rendering. The syntax could be a new attribute on the link element or a new value for "rel" attribute (that already have link ...
github.com
January 9, 2025 at 9:46 PM
It's long past time we had a standard way to load CSS asynchronously. link[async] should work just like the tried and true print-media hack, but without the major downside of javascript reliance for applying CSS.
Join me with a plus one here? github.com/whatwg/html/...
Join me with a plus one here? github.com/whatwg/html/...
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
Made this loader codepen.io/thebabydino/... half a decade ago. Then it only worked in Chromium browsers with the Experimental Web Platform features flag enabled.
As of 2024, it works cross-browser, no flags needed. Since someone hearting it reminded me of its existence, updated support info.
#CSS
As of 2024, it works cross-browser, no flags needed. Since someone hearting it reminded me of its existence, updated support info.
#CSS
January 7, 2025 at 10:18 AM
Made this loader codepen.io/thebabydino/... half a decade ago. Then it only worked in Chromium browsers with the Experimental Web Platform features flag enabled.
As of 2024, it works cross-browser, no flags needed. Since someone hearting it reminded me of its existence, updated support info.
#CSS
As of 2024, it works cross-browser, no flags needed. Since someone hearting it reminded me of its existence, updated support info.
#CSS
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
My Perf Calendar post made it just in time before the end of the year 😅
I wonked out on yielding strategies in loops, optimizing for more than just INP
calendar.perfplanet.com/2024/breakin...
I wonked out on yielding strategies in loops, optimizing for more than just INP
calendar.perfplanet.com/2024/breakin...
Breaking Up with Long Tasks or: how I learned to group loops and wield the yield
Everything, On the Main Thread, All at Once
Arrays are in every web developer's toolbox, and there are a dozen ways to iterate over them. Choose wrong, though, and all of that processing time will hap...
calendar.perfplanet.com
January 1, 2025 at 1:24 PM
My Perf Calendar post made it just in time before the end of the year 😅
I wonked out on yielding strategies in loops, optimizing for more than just INP
calendar.perfplanet.com/2024/breakin...
I wonked out on yielding strategies in loops, optimizing for more than just INP
calendar.perfplanet.com/2024/breakin...
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
Nice use of the JS Self-Profiling API by @sentry.io to debug INP issues
The fix was super satisfying too: replacing a slow JS library with pure CSS
Anyone else have success with it?
blog.sentry.io/improving-in...
The fix was super satisfying too: replacing a slow JS library with pure CSS
Anyone else have success with it?
blog.sentry.io/improving-in...
Improving INP and FID with production profiling
On March 12 Google began promoting INP (Interaction to Next Paint) into a Core Web Vital metric in an effort to push performance beyond page loads. This means y...
blog.sentry.io
December 19, 2024 at 2:00 AM
Nice use of the JS Self-Profiling API by @sentry.io to debug INP issues
The fix was super satisfying too: replacing a slow JS library with pure CSS
Anyone else have success with it?
blog.sentry.io/improving-in...
The fix was super satisfying too: replacing a slow JS library with pure CSS
Anyone else have success with it?
blog.sentry.io/improving-in...
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
I'm gradually cross-posting my work writing to my own site with canonical links to the original work post. I want to preserve them in case the original sites go down.
Here's the first one...
Struggling with loading speed on #Shopify sites? I've got you covered! #webperf
sia.codes/posts/debugg...
Here's the first one...
Struggling with loading speed on #Shopify sites? I've got you covered! #webperf
sia.codes/posts/debugg...
Debugging common causes for slow loading in Shopify Liquid storefronts | sia.codes
A smarter way to break down loading speed problems, identify causes, and implement optimizations
sia.codes
December 12, 2024 at 3:47 PM
I'm gradually cross-posting my work writing to my own site with canonical links to the original work post. I want to preserve them in case the original sites go down.
Here's the first one...
Struggling with loading speed on #Shopify sites? I've got you covered! #webperf
sia.codes/posts/debugg...
Here's the first one...
Struggling with loading speed on #Shopify sites? I've got you covered! #webperf
sia.codes/posts/debugg...
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
Some of you complain that PageSpeed Insights is a bit unrealistically show for the Lighthouse test.
The PSI servers are a bit underpowered so we're changing the throttling, which should make the Performance score go up when this rolls out in the next few weeks.
github.com/GoogleChrome...
🧵 1/5
The PSI servers are a bit underpowered so we're changing the throttling, which should make the Performance score go up when this rolls out in the next few weeks.
github.com/GoogleChrome...
🧵 1/5
Release v12.2.3 · GoogleChrome/lighthouse
Full Changelog
This release is only for PageSpeed Insights and we expect it to ship within 2 weeks.
Notable Changes
The CPU throttling factor for PageSpeed Insights has been adjusted (#16256) to ac...
github.com
December 5, 2024 at 4:36 PM
Some of you complain that PageSpeed Insights is a bit unrealistically show for the Lighthouse test.
The PSI servers are a bit underpowered so we're changing the throttling, which should make the Performance score go up when this rolls out in the next few weeks.
github.com/GoogleChrome...
🧵 1/5
The PSI servers are a bit underpowered so we're changing the throttling, which should make the Performance score go up when this rolls out in the next few weeks.
github.com/GoogleChrome...
🧵 1/5
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
Did you know that jQuery outperforms React, what? 😳
Sounds like clickbait, but is reality. The HTTP Archive shows 82% of sites that use jQuery have good INP on mobile📱, while only 67% do when they use React⚛️.
Not just sites, also libraries. Let's fix that👇#webperf
kurtextrem.de/posts/improv...
Sounds like clickbait, but is reality. The HTTP Archive shows 82% of sites that use jQuery have good INP on mobile📱, while only 67% do when they use React⚛️.
Not just sites, also libraries. Let's fix that👇#webperf
kurtextrem.de/posts/improv...
How To Improve INP: React⚛️
All-in-one guide for improving Interaction-to-Next-Paint (INP) Core Web Vital in React applications. Introduces the useAfterPaintEffect hook.
kurtextrem.de
December 2, 2024 at 4:07 PM
Did you know that jQuery outperforms React, what? 😳
Sounds like clickbait, but is reality. The HTTP Archive shows 82% of sites that use jQuery have good INP on mobile📱, while only 67% do when they use React⚛️.
Not just sites, also libraries. Let's fix that👇#webperf
kurtextrem.de/posts/improv...
Sounds like clickbait, but is reality. The HTTP Archive shows 82% of sites that use jQuery have good INP on mobile📱, while only 67% do when they use React⚛️.
Not just sites, also libraries. Let's fix that👇#webperf
kurtextrem.de/posts/improv...
Reposted by Jean-Pierre Vincent - #webperf & #greenit 🚀♻️🌱
Web Performance Calendar day 6 with Ana Boneva on instant pages and speculation rules and how we got here
calendar.perfplanet.com/2024/the-evo...
calendar.perfplanet.com/2024/the-evo...
The Evolution of Instant Web: What It Means for Performance Tooling
For years, traditional optimization techniques like caching and resource compression have been the go-to solutions for speeding up websites. They’ve been effective at reducing load times and easing se...
calendar.perfplanet.com
December 6, 2024 at 6:33 PM
Web Performance Calendar day 6 with Ana Boneva on instant pages and speculation rules and how we got here
calendar.perfplanet.com/2024/the-evo...
calendar.perfplanet.com/2024/the-evo...