juan ferreras

6 years of thinking I can make a better portfolio. 1 year of actually building it. My new portfolio is LIVE 🚀 Please, don't break anything! 👉 bruno-simon.com

Do you want a better Waterfall in Chrome DevTools? Then plus 1 this bug: issues.chromium.org/issues/34649... It's one of the things we're considering working on next but need to see that the interest is there, and it's not just a thing I'd like to see...

I spent hours and hours trawling through the sites of some of the world's best web developers, and despite the horrors I regularly experience in my daily work in Big JavaScript Territory, what I saw left me hopeful: infrequently.org/2025/07/links/

I'm looking to recruit talented senior engineers that have experience related to web performance monitoring and optimization. If that sounds like you—or someone you'd highly recommend—please send me a DM and I’ll share more details! The role is 100% remote and async-first.

This is incredible data from @dbelson.com showing HTML requests from crawlers versus referrals from that platform. Very easy to see the cost of AI here. ClaudeBot: 70.9k requests : 1 referral (!!!) OpenAI: 1.6K : 1 Perplexity: 202.4 : 1 blog.cloudflare.com/ai-search-cr...

This sounds super interesting. I'm a bit skeptical on how unit economics would work – but compared to we'll-try-to-scrape-everything-we-can-unless-you-can-sue-us-or-fully-block-us, it feels like a great alternative. Would love to see any leading provider send a positive signal..

Cloudflare's Containers are now in public beta. blog.cloudflare.com/containers-a... I was recently struggling to get a WASM version of brotli dictionary_generator (skill issue), but it's a very powerful unlock to just deploy a dockerfile if you need any specific runtime/CPU-intensive work

✨ THE SPDY STREAM ✨ is part of an effort to highlight people in performance and their projects. Show 001 tomorrow w/ @webx.bsky.social Join us! Want a LinkedIn link? DM me. ✨ THE SPDY STREAM ✨ 📅 Wednesday June 18th ⏰ 1pm EST, 13h00 CET 🗣️ Henri 🇨🇦, Vinicius 🇸🇪 🎟️ RSVP: bit.ly/spdy-stream-001

Cloudflare report on yesterday (Jun 12 2025) outage. Definitely respect the non name-shaming vendors policy and showing accountability/ownership instead. Very impressed by how detailed it is given it's been less than 24hs from it. blog.cloudflare.com/cloudflare-s...

"No major incidents"

⚡ Lighthouse (incorrectly) punishes preloading If you’re like me, you probably struggled with Lighthouse scores at least once. “I already optimized everything; why is my score still yellow?” Often, the cause is there’s more to optimize. But sometimes, it’s Lighthouse itself.

Yesterday's hit: llms.txt Today: llms-full.txt Tomorrow: llms-full-final.txt Twomorrow: llms-full-final-v2-this.txt

We only rate dogs. This is Chewbacca having a spa day. He's trying to relax. Please give him some privacy. 13/10

"AI should do my laundry" is something that not everyone agrees with but.. I'm surprised that tools that literally do all the errands I'm lazy to do haven't been nailed before trying to "replace" someone's job. E.g. repeat my coffee order, send invoice, pay rent, etc. Ideally with local models?

Parkinson's Law: all caches will expand themselves until your disk has basically no space left, regardless of the disk's total size.

The Chrome DevTools Performance panel just leveled up! 🚀 Here's a 69-second taste of the new hotness.

🔥 Simpler browser support info has landed in VS Code! Hover over any CSS property or HTML element or attribute and now you'll see its Baseline status 📝 web.dev/blog/baselin...

Ep. 3 will be on May 14! We will have Medhat Dawoud walking us through the process of building fast websites for everyone, and Amila Welihinda explaining how to profile JavaScript in production. #webperf Details at performanceobserver.dev

Chrome 136+ ships a new V8 version that supports a "compile hint", which makes V8 parse and compile all functions in that file eagerly. Great for entry points – where you know all functions will very likely be used. Less so as 'one weird trick to make all your JS faster'.

The @httparchive.org 's Web Almanac is looking for contributors for this year's edition. github.com/HTTPArchive/...

When Bruno Simon drops anything 3d on the web – it's a must to give it a try! I've already purchased his Three.js Journey course (check out the reviews if you're interested – folks seems to really love it!), planning to do it later this year. Something tells me it's going to be A LOT of fun

This is a beautiful and inspiring set of thoughts and illustrations on what UI could be wattenberger.com/thoughts/our...

For those monitoring Core Web Vitals, we made a small change to the CrUX History API used by CrUX Vis last night and now return 10 months of data, rather than 6 months of data to bring it more inline with the CrUX Dashboard that we're looking to deprecate. Enjoy! cruxvis.withgoogle.com#/

I've completely missed the fact Cloudflare Browser Rendering API now supports Playwright! I've had pretty good results using Puppeteer so far. TBC if variability is decent, etc but it's fun to script journeys (or export them from Chrome Recorder) to measure INP/CLS and still have results quickly

Compression Dictionary Transport allows you to DRASTICALLY reduce download sizes in Chrome. E.g. if you have app.v1.js and app.v2.js is released, a lot of the code is likely the same, so why download it all again? Want to know more? Check out this new guide: developer.mozilla.org/en-US/docs/W...

I'll publish it on LinkedIn later on today, but the startup I'm working at will undergo a 'reorg' aka layoffs. I'm part of it so If you are looking for a Staff / Lead Engineer with emphasis on FE and Perf hit me up (Remote or Hybrid within Stockholm / CET timezone)

Introducing Silk — The most advanced swipeable sheet ever engineered for the web. Native-like experience • Works on all devices • Unlocks dozens of UI patterns on the web. Available for React.

🚨 TypeScript just got 10× faster! The TypeScript compiler has been ported to Go and we had Anders Hejlsberg and Daniel Rosenwasser on to announce it and break it all down! www.youtube.com/watch?v=ZlGz...

The @performanceobserver.dev virtual meetup is back for its 2nd episode! We have @webx.bsky.social and @keerthanak17.bsky.social ready to guide us through another deep dive into #WebPerf Join us live! 📅 March 19th - 6 PM CET (10 AM PT / 1 PM ET) Details and add to calendar (with zoom link)👇

New in Chrome DevTools: Accurately emulate CPU performance of a low/mid tier phone with Automatic CPU throttling calibration! 📲 This feature calculates slow-downs for your specific device. Wanted this for years! We just shipped it.

what do y'all do with your unclosed tabs? I've been running pong inside all 240 of mine blog with a bunch of details over here: eieio.games/blog/running...

TIL Chromium might not handle SWR navigations as you'd expect (seems tracked by issues.chromium.org/issues/40171...). If you're implementing SWR in prod, make sure to test it on multiple browsers but also on your CDNs (even the Good Ones™ to this day have non-fully-spec-compliant implementations).

If there's one thing I could proudly be on a +P99 leaderboard is typing quickly on a keyboard. Super fun website – very interesting navigation! ---- 🏆 Today’s typ.ing: 🌟 Speed: 153wpm 🎯 Accuracy: 100.00% 📝 Training Set: English, most common 100 words 🔢 Capitalization: ❌ Numbers: ❌ Punctuation: ❌

LCP and INP are in Interop 2025!!!! web.dev/blog/interop...

Reminder that this changed rolled out in Chrome 133. If you’re seeing worse LCP times and load your LCP images from another domain (and didn’t have the TAO header set) then that could be why. Read the full thread for details.

What a beautiful surprise to get these extra fields on CrUX APIs! Absolutely fantastic work from the Chrome team, it's hard to describe how extremely useful it is to get this level of UX insight on almost any website, for free and without having to previously convince clients to setup monitoring

There are a number of announcements this month: First up, we have added LCP image subparts to the CrUX API: - Time to First Byte (TTFB) - Resource load delay - Resource load duration - Element render delay These are our recommended way of optimizing LCP: web.dev/articles/opt... 4/10

The Gap 🌟 An interactive article about the CSS gap property in Flexbox and Grid. 🔗 ishadeed.com/article/the-...

(1/2) Hello font-fancying folks, I'd like to gather data (and then release it in a form similar to caniuse) about the pre-installed fonts on each OS. The tool to gather the data (using queryLocalFonts, so Chrome-only) is fontes-locais.vercel.app, an example data: github.com/stoyan/fonte... ...

Not sure if this is a good idea (or a terrible one!) but Canvas and WebRTC APIs are pretty great! TBC on how accurate (this is PSI's Lighthouse, should also be compat with CF Workers Puppeteer and probably more accurate but screencasts have a weird gamma offset unfortunately).

New in Chrome DevTools: Skip irrelevant scripts in the Flame Chart! Debugging is faster and more actionable 🙏

The web can be incredible sometimes, specially when talented folks do great things with care

It's not DNS. There's no way it's DNS. It was DNS.