Karlijn Löwik
@karlijnlowik.bsky.social
CEO & Co-founder @RUMvision | Simplifying web performance | Women in tech advocate | Toddler mom | International speaker | Lover of memes | Co-chair RUM W3C | Board member Mage-OS NL
Feels like this bio is getting really long😅
Feels like this bio is getting really long😅
Reposted by Karlijn Löwik
Yeeeessssss! 🤩
Gecko: Intent to prototype and ship: View transition types
Gecko: Intent to prototype and ship: View transition types
Gecko: Intent to prototype and ship: View transition types
groups.google.com
November 23, 2025 at 6:40 PM
Yeeeessssss! 🤩
Reposted by Karlijn Löwik
This is desperately needed on iOS.
On the Edge team, we think web apps should be easier to install.
The default browser install button is great, but we'd like something which you can use on your own site, how and when you want it.
That's why we're proposing the Web Install API, which you can now test!
The default browser install button is great, but we'd like something which you can use on your own site, how and when you want it.
That's why we're proposing the Web Install API, which you can now test!
The Web Install API is ready for testing
We're happy to announce that the Web Install API is now ready for testing on your own site, as an origin trial in Microsoft E
blogs.windows.com
November 24, 2025 at 5:29 PM
This is desperately needed on iOS.
Reposted by Karlijn Löwik
Inspired by perfnow.nl, I've dusted off drafts of my network and device situation analysis. Good news/bad news: devices and networks are improving, but pages are swelling. The web is usable for the wealthy, but less so for everyone else.
infrequently.org/2025/11/perf...
infrequently.org/2025/11/perf...
The Performance Inequality Gap, 2026 - Infrequently Noted
Embedded in this year's network and device estimates is hopeful news about the trajectory of devices and networks. It has never been easier to deliver pages quickly, but we are not collectively…
infrequently.org
November 24, 2025 at 7:31 PM
Inspired by perfnow.nl, I've dusted off drafts of my network and device situation analysis. Good news/bad news: devices and networks are improving, but pages are swelling. The web is usable for the wealthy, but less so for everyone else.
infrequently.org/2025/11/perf...
infrequently.org/2025/11/perf...
Gosh, such a hard life. On the race track of F1 in Zandvoort😄
November 20, 2025 at 2:41 PM
Gosh, such a hard life. On the race track of F1 in Zandvoort😄
Reposted by Karlijn Löwik
The "i" in "iPhone" stands for "inequality", late 2025 edition:
November 18, 2025 at 3:51 AM
The "i" in "iPhone" stands for "inequality", late 2025 edition:
Reposted by Karlijn Löwik
This was performance.now() 2025
YouTube video by Web Conferences Amsterdam
www.youtube.com
November 4, 2025 at 11:51 AM
Reposted by Karlijn Löwik
performance.now() 2026 will take place on 19th and 20th of November 2026. #perfnow.
November 1, 2025 at 8:21 AM
performance.now() 2026 will take place on 19th and 20th of November 2026. #perfnow.
We had an amazing time at #perfnow once again! Thanks everyone ♥️
As a final note, old man yells at cloud @cliffcrocker.bsky.social, amazing costume!
As a final note, old man yells at cloud @cliffcrocker.bsky.social, amazing costume!
November 1, 2025 at 10:08 AM
We had an amazing time at #perfnow once again! Thanks everyone ♥️
As a final note, old man yells at cloud @cliffcrocker.bsky.social, amazing costume!
As a final note, old man yells at cloud @cliffcrocker.bsky.social, amazing costume!
Folks from #perfnow, general PSA, there will be issues with ALL the trains to Schiphol Airport, not just Amsterdam Central, expected until 12.15
Article in Dutch: Geen treinverkeer tussen Amsterdam en Schiphol - nos.nl/l/2588749
Article in Dutch: Geen treinverkeer tussen Amsterdam en Schiphol - nos.nl/l/2588749
Geen treinverkeer tussen Amsterdam en Schiphol
Door geplande werkzaamheden reden er dit weekend sowieso al geen treinen tussen Amsterdam Centraal en Schiphol. Maar nu is er ook nog een seinstoring.
nos.nl
November 1, 2025 at 10:05 AM
Folks from #perfnow, general PSA, there will be issues with ALL the trains to Schiphol Airport, not just Amsterdam Central, expected until 12.15
Article in Dutch: Geen treinverkeer tussen Amsterdam en Schiphol - nos.nl/l/2588749
Article in Dutch: Geen treinverkeer tussen Amsterdam en Schiphol - nos.nl/l/2588749
Reposted by Karlijn Löwik
October 31, 2025 at 1:48 PM
We had a great first Real User Meeting (a.k.a RUM RUM) at Google Amsterdam today via our W3C RUM Group today!
Great way to kick off #perfnow, with 70 people working on building a RUM+ updates from both Firefox and Chrome🚀😄
Great way to kick off #perfnow, with 70 people working on building a RUM+ updates from both Firefox and Chrome🚀😄
October 29, 2025 at 4:02 PM
We had a great first Real User Meeting (a.k.a RUM RUM) at Google Amsterdam today via our W3C RUM Group today!
Great way to kick off #perfnow, with 70 people working on building a RUM+ updates from both Firefox and Chrome🚀😄
Great way to kick off #perfnow, with 70 people working on building a RUM+ updates from both Firefox and Chrome🚀😄
Traveling to the train, Dutch style (yes that is @erwinhofman.bsky.social juggling a suitcase on a bike😆)
October 29, 2025 at 8:53 AM
Traveling to the train, Dutch style (yes that is @erwinhofman.bsky.social juggling a suitcase on a bike😆)
Child dropped off, voted (it's general election today in the Netherlands) and on our way to #perfnow by train! See many of you in 3 hours at the RUM RUM at Google😀
October 29, 2025 at 8:14 AM
Child dropped off, voted (it's general election today in the Netherlands) and on our way to #perfnow by train! See many of you in 3 hours at the RUM RUM at Google😀
With everyone in the webperformance sphere in the Netherlands for #perfnow let me send you a sunny picture from Mallorca😀 On our way back to NL tomorrow🇳🇱
October 27, 2025 at 6:34 PM
With everyone in the webperformance sphere in the Netherlands for #perfnow let me send you a sunny picture from Mallorca😀 On our way back to NL tomorrow🇳🇱
Reposted by Karlijn Löwik
Largest Contentful Paint (from Core Web Vitals) is now available in Safari Technology Preview.
webkit.org/blog/17504/r...
webkit.org/blog/17504/r...
Release Notes for Safari Technology Preview 230
Safari Technology Preview Release 230 is now available for download for macOS Tahoe and macOS Sequoia.
webkit.org
October 16, 2025 at 8:53 PM
Largest Contentful Paint (from Core Web Vitals) is now available in Safari Technology Preview.
webkit.org/blog/17504/r...
webkit.org/blog/17504/r...
Ha. But also, yes, that is scary 😂
October 16, 2025 at 10:26 AM
Ha. But also, yes, that is scary 😂
Live! Fast and Curious webinar with Jordy Scholing (RUMvision) and Wouter Steenmeijer (Elgentos), where they will break websites Core Web Vitals, and fix them again.
While messing around and answering important live questions like "Kroket vs Eierbal" Watch here: streamyard.com/watch/iUTmXn...
While messing around and answering important live questions like "Kroket vs Eierbal" Watch here: streamyard.com/watch/iUTmXn...
October 16, 2025 at 9:12 AM
Live! Fast and Curious webinar with Jordy Scholing (RUMvision) and Wouter Steenmeijer (Elgentos), where they will break websites Core Web Vitals, and fix them again.
While messing around and answering important live questions like "Kroket vs Eierbal" Watch here: streamyard.com/watch/iUTmXn...
While messing around and answering important live questions like "Kroket vs Eierbal" Watch here: streamyard.com/watch/iUTmXn...
Reposted by Karlijn Löwik
Safari TP 230 includes support for Largest Contentful Paint 🙌 #webperf
Webkit: Release Notes for Safari Technology Preview 230
Webkit: Release Notes for Safari Technology Preview 230
Webkit: Release Notes for Safari Technology Preview 230
webkit.org
October 15, 2025 at 9:27 PM
Safari TP 230 includes support for Largest Contentful Paint 🙌 #webperf
Reposted by Karlijn Löwik
I spy with my little eye both INP and LCP enabled by default in the latest Safari Tech Preview.
What with Firefox landing INP in stable yesterday (on top of LCP that they already supported) this means we'll soon have cross-browser support for these two Core Web Vitals!
#interop2025 #CoreWebVitals
What with Firefox landing INP in stable yesterday (on top of LCP that they already supported) this means we'll soon have cross-browser support for these two Core Web Vitals!
#interop2025 #CoreWebVitals
October 15, 2025 at 9:49 PM
I spy with my little eye both INP and LCP enabled by default in the latest Safari Tech Preview.
What with Firefox landing INP in stable yesterday (on top of LCP that they already supported) this means we'll soon have cross-browser support for these two Core Web Vitals!
#interop2025 #CoreWebVitals
What with Firefox landing INP in stable yesterday (on top of LCP that they already supported) this means we'll soon have cross-browser support for these two Core Web Vitals!
#interop2025 #CoreWebVitals
Reposted by Karlijn Löwik
Nerdy stuff! @mozilla.org #Firefox just enabled support for #INP with v144 🎉
I dived into our raw RUMvision data. And yep, can confirm that it works when using Google's web-vitals #JavaScript library 😍
(updated) article + chart + baseline badges in a blogpost:
www.rumvision.com/blog/firefox...
I dived into our raw RUMvision data. And yep, can confirm that it works when using Google's web-vitals #JavaScript library 😍
(updated) article + chart + baseline badges in a blogpost:
www.rumvision.com/blog/firefox...
October 15, 2025 at 8:19 AM
Nerdy stuff! @mozilla.org #Firefox just enabled support for #INP with v144 🎉
I dived into our raw RUMvision data. And yep, can confirm that it works when using Google's web-vitals #JavaScript library 😍
(updated) article + chart + baseline badges in a blogpost:
www.rumvision.com/blog/firefox...
I dived into our raw RUMvision data. And yep, can confirm that it works when using Google's web-vitals #JavaScript library 😍
(updated) article + chart + baseline badges in a blogpost:
www.rumvision.com/blog/firefox...
Reposted by Karlijn Löwik
Firefox 144 now supports INP! 🦊
We just shipped interactionId, the piece that makes Interaction to Next Paint work. It helps browsers connect events from the same interaction and measure how responsive pages really feel.
More here: blog.mozilla.org/performance/...
We just shipped interactionId, the piece that makes Interaction to Next Paint work. It helps browsers connect events from the same interaction and measure how responsive pages really feel.
More here: blog.mozilla.org/performance/...
Firefox 144 ships interactionId for INP – Mozilla Performance
TL;DR Firefox 144 ships PerformanceEventTiming.interactionId, which lets browsers and tools group events that belong to the same user interaction. This property is used to calculate Interaction to Nex...
blog.mozilla.org
October 15, 2025 at 12:46 PM
Firefox 144 now supports INP! 🦊
We just shipped interactionId, the piece that makes Interaction to Next Paint work. It helps browsers connect events from the same interaction and measure how responsive pages really feel.
More here: blog.mozilla.org/performance/...
We just shipped interactionId, the piece that makes Interaction to Next Paint work. It helps browsers connect events from the same interaction and measure how responsive pages really feel.
More here: blog.mozilla.org/performance/...
Ha! Hema now sells bitterballen stuffies, that is hilarious. And stroopwafel, rookworst and tompouce 😀🇳🇱
Love them.
Love them.
October 11, 2025 at 3:36 PM
Ha! Hema now sells bitterballen stuffies, that is hilarious. And stroopwafel, rookworst and tompouce 😀🇳🇱
Love them.
Love them.
Guess who was feeling creative and made a prize for @erwinhofman.bsky.social upcoming SEO Benelux quiz 😉
October 8, 2025 at 4:23 PM
Guess who was feeling creative and made a prize for @erwinhofman.bsky.social upcoming SEO Benelux quiz 😉