Joan León 🏞️⚡️

⚡️ Web Performance Artisan at @perfreviews_ | @GoogleDevExpert in #WebTech | @cloudinary Ambassador

[Joan León 🏞️⚡️ @nucliweb]

I have published a website with Web Performance Snippets to make it more user-friendly, more orderly, and with a search feature

⚡️💾 https://t.co/fDpDDY46zs

#WebPerf #Performance #PerfTools

[Carles Núñez Tomeo @carlesnunez]

🔮 Built a real-time click prediction right over the DOM using JEV that feels like a crystal ball.

Powered by jev-latest to predict the next clickable element and intent in 345ms per check, highlighting candidate elements on screen.

It's extremely cheap to use and helps predict user intention, hitting 83% accuracy in testing.

Usages that come to my mind:
- Web performance optimization via predictive resource load
- UX Research and testing
- Progressive UI loading based on intention
- Accessibility for reduced motor precision (highlight based on intention allowing to click, for example)
- And probably many more...

[WebPerformance Report @WebPerfReport]

⚡Featured posts this week:
✨ New ad metrics in CrUX: @alextcone
✨ The case against JPEG XL: Gianni Rosato
✨ Why Spotify Is Not Using Bayesian A/B Testing: Mattias Frånberg, Mårten Schultzberg
✨ International SEO: Barry Adams
🙏 Special thanks to the authors!
#webperf

[Joan León 🏞️⚡️ @nucliweb]

The case against JPEG XL

Investigating JPEG XL's place as a Web image codec, by Gianni Rosato, via @WebPerfReport

https://t.co/ppNUDEvfEH

#JPEGXL #JXL #ImagePerf #WebPerf

[Joan León 🏞️⚡️ @nucliweb]

@carlesnunez 🤩 Solo digo: Speculation Rules API, preload, prefetch, preconnect.

Con esas ideas, ojo que @PerfReviews_ no te quiera fichar ☺️

[Sarah Drasner @sarah_edo]

Agent: *screenshots the page*
Agent: *scrolls*
Agent: *screenshots again*
Agent: *clicks the wrong button*
Agent: *screenshots again*
Page with WebMCP: hi, here are the 4 things you can do here, with descriptions
Agent: oh thank god

[Chrome for Developers @ChromiumDev]

Modern Web Guidance v0.0.187 brings new and updated guides and Codex plugin support → https://t.co/7Gk5Y0SL0a

✨ New guides: progress rings, scrollspy nav menus, loading spinners
📝 Updated guidance to avoid bfcache breakage and unwanted inline layout gaps
🔌 Added plugin manifest support for Codex

[Chrome for Developers @ChromiumDev]

10,000 installs and counting! 📈 We created Modern Web Guidance to bring web platform expertise right into your agent workflows. Have you tried pairing these skills with Chrome DevTools for agents to audit performance and automatically fix code?

Check it out and join 10K+ web developers who are coding smarter → https://t.co/9bmqAirdxP

[Joan León 🏞️⚡️ @nucliweb]

An agent shouldn't have to guess CSS selectors to read a conference schedule.

I implemented WebMCP on the GeeksCAT Conf 2026 website: a static Astro site, no server.

https://t.co/4MRw3mxHmN

#WebMCP

[Chrome for Developers @ChromiumDev]

Open up your app's inner workings to AI agents with custom tools in DevTools for agents→ https://t.co/3R3KEqZMNE

Write plain JavaScript to build tailored third-party tools that save tokens and bypass manual steps like login forms built for humans.

[Sarah Drasner @sarah_edo]

🔥 It was an absolute pleasure to talk about WebMCP among other AI on the web topics with @domfarolino on the latest @syntaxfm!

Along with the rest of the internet, @wesbos and @stolinski are heroes of mine. Thank you for hosting us!

https://t.co/GMBaBm2b0X

[Joan León 🏞️⚡️ @nucliweb]

P75 is green: LCP 1.58s, INP 176ms, CLS 0.01. P90: LCP 2.68s, INP 352ms, CLS 0.17. 15% of visits get a noticeably worse experience.

Product Performance doesn't end once you pass CrUX. If P75 is good, work on P90.

#WebPerf #CoreWebVitals #ProductPerformance

[WebPerformance Report @WebPerfReport]

⚡Featured posts this week:
✨ Submit your proposals for Interop 2027: @rachelandrew
✨ Reading a performance profile: @nucliweb
✨ HTML over WebSockets: @androsfenollosa
✨ Intro to Web UX and Speed Optimization: @sergeyche
🙏 Special thanks to the authors!
#webperf

[Chrome for Developers @ChromiumDev]

Here's what's new in Modern Web Guidance v0.0.186 → https://t.co/ZzH2rnoZgu

⌨️ New guide on IME-safe textarea submission, along with recs for handling KeyboardEvent.isComposing for IME

🔎 Mandatory code verification step for agents in the global MWG skill

[WebPerformance Report @WebPerfReport]

Three Reports.
One Multidimensional UX Benchmark: @Nintendo
Built for C-level readers.

Full benchmark in the comments 👇

[Addy Osmani @addyosmani]

"The most important skill in prompting is expertise in the domain you’re prompting for"

https://t.co/Dgme0HcL2z

Sometimes the human is the bottleneck. A good reminder LLMs are a force multiplier if you're skilled and to build this domain expertise if you don't have it yet.

[Jyrki Alakuijala 🇺🇦 @jyzg]

I'm leaving Google after 20 years and creating 5 internet formats (WebP lossless, Brotli, Shared Brotli, WOFF2, JPEG XL) and impacting 5 other data formats (PDF, EPUB, DICOM, Digital Negative, ProRAW). It was good times.

https://t.co/aNxkiVEqkU

[Matt Zeunert @mattzeunert]

My Pixel Pioneers talk is on Youtube now!

I give a brief introduction to page speed and then dive into different network throttling methods in Lighthouse, DevTools, and other tools.

https://t.co/xwRo89YqT9

[Addy Osmani @addyosmani]

"Don't paste the AI, please"

"The world is full of people who don't want to read or think things through. Don't be one of them."

https://t.co/aCuUH0Sgpo

[PerfReviews ⚡️ @PerfReviews_]

“The performance issues erode trust. Users rarely report performance problems directly; they simply leave, convert less often, or switch to competitors.” - @denodell

https://t.co/Bq2PggIL3t

#WebPerf #FastByDefault #PerfEngineering

[Matt Zeunert @mattzeunert]

We've improved support for server timing headers in DebugBear!

📊 Breakdown view in request details
⚙️ Automatic server timing tracking in synthetic monitoring
📈 Track server timings as a custom RUM metric