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Reposted by Joan León

DebugBear @debugbear.com · 1d

MCP servers act as the connection between AI models and other software.

Our new article explains how you can use the Chrome DevTools MCP to debug web performance issues.

www.debugbear.com/blog/chrome-...

Performance Debugging With The Chrome DevTools MCP Server | DebugBear

Learn how to use the Chrome DevTools MCP server with AI models to analyze web performance and get concrete optimization recommendations.

www.debugbear.com

1 5

Reposted by Joan León

Cloudflare @cloudflare.social · 15h

Cloudflare investigated performance benchmark results for Workers, uncovering and fixing issues, making Workers faster for all customers.

https://blog.cloudflare.com/unpacking-cloudflare-workers-cpu-performance-benchmarks/

Unpacking Cloudflare Workers CPU Performance Benchmarks

Cloudflare investigated CPU performance benchmark results for Workers, uncovering and fixing issues in infrastructure, V8 garbage collection, and OpenNext optimizations. These improvements have made C...

blog.cloudflare.com

4 23

Joan León @nucliweb.net · 13h

Yes, I know… definitely some room for improvement here! Let’s make it better. 🚀

Joan León @nucliweb.net · 13h

Collecting the first INP data from Firefox 144 🤩

#WebPerf #INP #CoreWebVitals #Performance #Firefox #PerfTools

Screenshot of the DebugBear performance monitoring dashboard showing Interaction to Next Paint (INP) metrics filtered for Firefox on desktop. The main metric shows an INP value of 336 milliseconds, categorized as “Needs Improvement.” A tooltip on a trend chart indicates that on October 15, 2025, the INP rating was “Needs Improvement” with one view and 50% of interactions affected. A world map highlights data from a region in Europe.

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Reposted by Joan León

Una Kravets @una.im · 1d

The #CSSPodcast is back! 💕🎙️

Join @bram.us and I this season as we talk about a bunch of awesome new CSS features, starting with custom functions and if()

thecsspodcast.libsyn.com/92-css-if-an...

The CSS Podcast: 92: CSS if() and custom functions

Welcome back to the new season of the CSS Podcast, where Una and Bramus are your guides, your cohosts, and your CSS best friends. In this episode we dig into two very powerful new CSS features: inlin...

thecsspodcast.libsyn.com

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Reposted by Joan León

Barry Pollard @tunetheweb.com · 13d

Core Web Vitals mystery for ya:

Why does Google Search Console same my LCP is bad, but every example URL has good LCP?

I see developers asking: How can this happen? Is GSC wrong? (I'm willing to bet it is not!) What can you do about it?

This is admittedly confusing so let's dive in...

🧵 1/12

Screenshot of Core Web Vitals graph in Google Search Console, with the URLs greyed out. The Group LCP is 2.6 seconds and so the group is in amber and saying there is an issue as it's longer than the 2.5 seconds "good" threshold. Yet all the examples have green LCPs of 1.7 seconds, 2.4 seconds, 1.2 seconds...etc. which is confusing.

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Joan León @nucliweb.net · 16d

New Web Performance challenge, improve the INP and LCP of this Web App.

Interaction to Next Paint
🟥 920ms in desktop
🟥 1800ms in mobile

Largest Contentful Paint
🟩 2.33s in desktop
🟥 4.13s in mobile

#WebPerformance #CoreWebVitals #INP

4

Joan León @nucliweb.net · 23d

One List To Rule Them All

nerdy.dev/cascading-se...

#CSS

One List To Rule Them All · September 10, 2025

In the darkness may it bind us

nerdy.dev

2 6

Reposted by Joan León

Thomas Steiner @tomayac.com · 29d

On the Chrome team, we've a cool new origin trial for you to try in your apps: the Proofreader API: developer.chrome.com/docs/ai/proo....

❌ tyop → ✅ typo

```js
await (await Proofreader.create({
expectedInputLanguages: ['en'],
})).proofread(
'Let us knwo how it foes',
);
```

#BuiltInAI #WebAI

The Proofreader API | AI on Chrome | Chrome for Developers

Improve your content readability and grammar with the Proofreader API.

developer.chrome.com

2 6 25

Joan León @nucliweb.net · 28d

📣 New version

Perfetto v52.0

github.com/google/perfe...

#WebPerf #PerfTools

Release Perfetto v52.0 · google/perfetto

We’re excited to share some highlights from the Perfetto v52 release. 🌙 Dark mode support The Perfetto UI now features a dark mode with theme-aware colors! Dark mode can be enabled via"settings" i...

github.com

1 3

Joan León @nucliweb.net · Sep 15

200+ Resources to Become a Great Engineering Leader in 2025

newsletter.eng-leadership.com/p/200-resour..., by @gregorojstersek.bsky.social

#Engineering

200+ Resources to Become a Great Engineering Leader in 2025

List of books, newsletters & articles, people and more!

newsletter.eng-leadership.com

1 1

Joan León @nucliweb.net · Sep 10

A basic package to quickly check if your npm project is using malicious versions of npm packages

github.com/oegea/is-my-...

GitHub - oegea/is-my-code-pwned: A basic package to quickly check if your npm project is using malicious versions of npm packages

A basic package to quickly check if your npm project is using malicious versions of npm packages - oegea/is-my-code-pwned

github.com

2 5

Joan León @nucliweb.net · Sep 9

#TIL You can sent multiple Server-Timing headers

Screenshot of HTTP response headers showing three Server-Timing entries: cfCacheStatus with value HIT, cfOrigin with duration 0 and cfEdge with duration 18, and cfExtPri with no value.

Joan León @nucliweb.net · Aug 25

github.com/calibreapp/i...

GitHub - calibreapp/image-actions: A Github Action that automatically compresses JPEGs, PNGs and WebPs in Pull Requests.

A Github Action that automatically compresses JPEGs, PNGs and WebPs in Pull Requests. - calibreapp/image-actions

github.com

1 2

Joan León @nucliweb.net · Aug 25

#WebPerfTip

If you need a GitHub Action to automatically compresses JPEGs, PNGs and WebPs in pull requests, IMHO this is the best option

#WebPerf #ImagePerf #PerfTools #Image

GitHub Actions bot comment showing that images were automatically compressed by Calibre’s image-actions. The comment reports a 47.1% reduction in image size, saving 104.46 KB. A table displays one example file (‘Screen Shot 2020-09-17 at 3.29.33 pm.png’) reduced from 221.87 KB to 117.41 KB. It notes that 348 images did not require optimisation, and includes a ‘View diff’ link for visual comparison.

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Reposted by Joan León

SquiggleConf @squiggleconf.com · Aug 22

Want to debug your web app’s performance? DevTools has the answers: you just need to know where to look. @rviscomi.dev explains the hidden, upcoming, and all-around useful features of the Performance panel at SquiggleConf 2024.

youtu.be/nJ-h7UWdXZA

The Chrome DevTools Performance Panel | Rick Viscomi

YouTube video by SquiggleConf

youtu.be

2 3 7

Reposted by Joan León

Harry Roberts @csswizardry.com · Aug 22

👀 I’ve been working on a little something! There’s a link to the demo in the video description.

www.youtube.com/watch?v=IMww...

Obs.js Preview – Adapt to user context

YouTube video by Harry Roberts

www.youtube.com

1 1 9

Joan León @nucliweb.net · Aug 21

Test TTFB From Multiple Test Locations
www.debugbear.com/test/ttfb
by @debugbear.com

TTFB Test: Check Time to First Byte On Your Website

Measure Time to First Byte performance from multiple global test locations.

www.debugbear.com

1 4

Joan León @nucliweb.net · Aug 21

Do you have a website with international visitors?

Check the Time to First Byte (TTFB) from different locations, and create a plan to improve it if your visitors are having a bad experience.

Start testing today, links in the first comment.

#WebPerf #PerfTools #Performance #TTFB

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Joan León @nucliweb.net · Aug 14

🔍 Found in a recent web performance audit:
favicon.ico → 301 redirect → broken URL → returns 13 MB uncompressed HTML

⚠️ Even tiny assets can slow your site if misconfigured.
Check static files (favicon, images, CSS, JS) — small issues add up

#WebPerf #WebPerformance #Frontend #DevTips