In my audits, reading the Performance profile is where people get stuck: the flame chart and waterfall look like noise at first I built an interactive guide to make them click, every figure is interactive, plus LCP, CLS, INP and the Insights panel perf.reviews/profile-guide #WebPerf #DevTools

Reading a Performance Profile: Field Guide

An interactive field guide to the Chrome DevTools Performance panel: waterfall, flame chart, LCP, CLS, INP, and the Insights panel.

perf.reviews

An occupational habit: I open DevTools on every site I visit, hunting for things to improve. On skills.addy.ie I caught a 301 on every internal click, a wasted round trip. It was a trailing-slash mismatch. Wrote up the finding and the fix: joanleon.dev/en/trailing-... #WebPerf #Astro #Netlify

“Most teams fall into a reactive performance decay cycle: ship, wait for complaints, panic, patch, repeat. The Fast by Default model provides a repeatable alternative that keeps systems healthy.” Performance Engineering in Practice, by @denodell.bsky.social #WebPerf #Performance

Llevo tiempo viendo demos de multiagentes y casi todas sufren de lo mismo: un agente escribe y otro revisa... para acabar haciendo una todo-app No son malas demos, pero no hay un motivo técnico real para dividirlas en agentes. Así no aprendemos cuándo sí tiene sentido Hilo con una alternativa 👇

Safari and Firefox change how big sites render based on the domain. TikTok, Netflix, Instagram… even SeatGuru. Chrome doesn’t. Why is that? denodell.com/blog/browser... by @denodell.bsky.social #Browser

Browsers Treat Big Sites Differently

Safari and Firefox change how big sites render based on the domain. TikTok, Netflix, Instagram… even SeatGuru. Chrome doesn’t. Why is that?

denodell.com

¿Buscas optimizar el rendimiento de tus aplicaciones con agentes de IA? En este workshop aprenderás a conectar el Chrome DevTools MCP a un agente para automatizar la detección de problemas. Veremos cómo generar reportes técnicos, de cliente y de management 👇 ¡Inscríbete aquí! #WebPerf #AI #MCP

Joan León@nucliweb.net · 3mo ago

El agente de IA no sabe debuggear rendimiento si tú no le das el contexto para hacerlo. No es que sea malo. Por defecto trabaja a ciegas: sin acceso al navegador, sin trazas reales. #WebPerf #Performance #AIAgents #ChromeDevTools #Frontend

Running performance audits by hand, scripts in DevTools, results scattered, is fine until you're doing it on every project I built PerfReviews Insights to skip that. URL in, structured report out. Fonts, images, CSS, LCP, TTFB. Pro accounts keep full history perf.reviews/insights #WebPerf

PerfReviews Insights — Web Performance Analyzer

Analyze any website and get an instant performance report: images, videos, third-party scripts, and page weight.

perf.reviews

El agente de IA no sabe debuggear rendimiento si tú no le das el contexto para hacerlo. No es que sea malo. Por defecto trabaja a ciegas: sin acceso al navegador, sin trazas reales. #WebPerf #Performance #AIAgents #ChromeDevTools #Frontend

WebPerf Snippets meets AI agents: Orchestration without hallucination slides.com/joanleon/web... #WebPerf #WebPerfSnippets #PerfTools

WebPerf Snippets meets AI agents: Orchestration without hallucination

WebPerf Snippets evolved from manual DevTools scripts into an open-source project. Now, it explores a nervous question: Can AI help with web performance? The answer is yes, provided the LLM doesn't m...

slides.com

Join us tomorrow for two great talks from Alfonso Moure and @nucliweb.net ! #webperf All details at... performanceobserver.dev

PerformanceObserver: A virtual web perf meetup

Join the PerformanceObserver virtual performance meetup to get all the latest web performance news and hang out with the community.

performanceobserver.dev

I've finished the #WebGPU in the browser series. 4 articles: fundamentals, image processing, real-time ML, and video editing Never written a shader before starting. In the last article we process video at 2ms per frame with WebGPU + WebCodecs joanleon.dev/en/webgpu-br... #WebPerf #JavaScript

WebGPU: the browser's new performance engine | Joan León

WebGPU exposes the GPU directly to the browser, opening new possibilities for intensive processing: images, video, ML, and more.

joanleon.dev

Toggle CSS classes in bulk, then reset the scroll: two lines that force the browser to block the main thread synchronously. I documented how to detect it in the Performance Panel and why one requestAnimationFrame is not enough to fix it. #WebPerf #CSS #DevTools #JavaScript

The DebugBear custom dashboards feature is live now! We provide a flexible interface where you can display the web performance data that matters to your team. youtu.be/96fFkixiC8Y

How to create custom web performance dashboards for your team

YouTube video by DebugBear

youtu.be

Thanks to Codemotion for giving me the opportunity to continue sharing my knowledge on #WebPerf (aka improving the UX), and to do so in a workshop format where we use Chrome DevTools MCP to identify performance issues on a website with AI agents. #WebPerf #PerfTools #DevTools #CodemotionMadrid

A Gaussian blur in Canvas 2D takes 280ms. The same filter with WebGPU: 8ms. I wrote the second article in the WebGPU series: image processing in the browser with WGSL shaders and real benchmarks. joanleon.dev/en/webgpu-im... #WebPerf #WebGPU #JavaScript #Performance

Image processing in the browser with WebGPU | Joan León

How to use WebGPU to apply filters and transformations to images in the browser. Real benchmarks comparing with Canvas 2D.

joanleon.dev

Joan León@nucliweb.net · 4mo ago

For years, the performance ceiling in the browser has been clear: the CPU. WebGPU changes that. 🧵 It’s not a library or a framework. It’s a browser API that gives direct access to the device’s GPU, enabling a level of parallelism the CPU cannot match. #WebPerf #WebGPU

I wrote about the experimental chrome-devtools-mcp CLI: a persistent daemon and direct subcommands to control Chrome from the terminal without writing code. Network, performance, Lighthouse, memory, interactions. All from the shell. joanleon.dev/en/chrome-de... #WebPerf #DevTools #JavaScript

Automate the browser from the terminal with Chrome DevTools MCP CLI | Joan León

The chrome-devtools-mcp package includes an experimental CLI that lets you control Chrome directly from the terminal: navigate, interact, audit performance, analyze network and memory, all without lea...

joanleon.dev

Just published the first article of a series. Covers what WebGPU is, CPU vs GPU for performance, and when to use it (vs WebAssembly). Next: image processing, ML inference, and real-time video, with real code and benchmarks. 👉 joanleon.dev/en/webgpu-br... #WebPerformance #WebGPU #JavaScript

WebGPU: the browser's new performance engine | Joan León

WebGPU exposes the GPU directly to the browser, opening new possibilities for intensive processing: images, video, ML, and more.

joanleon.dev

Sometimes opportunities come along that push you out of your comfort zone. An international product, millions of visits, and impact at scale. Definitely an exciting challenge. #WebPerf #CoreWebVitals #PerfChallenge

Software is evolving fast. My focus hasn’t changed: helping teams improve performance, UX, and conversion AI generates working code faster than ever… but not optimized for performance That’s where we add value: from “it works” to “it’s excellent” Reading @addyosmani.bsky.social’s new book

WebPerformance Report is no longer just a weekly report in your inbox Well done, @webperfreport.bsky.social team #WebPerf #Accessibility #Performance #Security #WebPerfReport

WebPerformance Report@webperfreport.bsky.social · 4mo ago

⚡WebPerformance Report is more than a report in your inbox. Users also get access to their Board to manage reports, review deliveries, and follow Performance, Accessibility, and Security trends over time. Get your report here: 👉https://webperformancereport.com/ #webperf

Testing PerfReviews Insights #WebPerf #Performance #PerfReviews #CoreWebVitals

A measurement that varies with the model's interpretation is not a measurement. It's an estimate. I've written about separating deterministic measurement from AI analysis in web performance audits. #WebPerf #Performance #PerfReview #AI #DevTools

IA en auditorías de Web Performance: medición determinística e informes accionables perf.reviews/blog/ai-web-... #WebPerf #Performance #PerfReviews #PerfAudit #AI

IA en auditorías de Web Performance: medición determinística e informes accionables

Cómo combinar scripts determinísticos y agentes de IA para ir de la recopilación de métricas a un informe accionable, y sentar las bases del test de regresión continuo en rendimiento.

perf.reviews

React SSR Framework Showdown: TanStack Start, React Router, and Next.js Under Load blog.platformatic.dev/react-ssr-fr... by @nodeland.dev #React #Performance

🚀 PerfReviews Insights: two new metrics to audit your web performance We've added two new analyses to the tool: #WebPerf #Performance #PerfReviews #WebPerfInsights

Muchas webs siguen sirviendo imágenes PNG de 2–3 MB. Pero esas mismas imágenes pueden pesar menos de 50 kB. La optimización de imágenes sigue siendo uno de los mayores problemas de rendimiento en la web. Hilo 👇

Chrome is bringing AI directly into the browser with the Summarizer API. In this post I show how to add an AI-generated summary to blog posts using the Chrome Summarizer API and models running locally in the browser. No external APIs. No token costs. #AI #WebAI #JavaScript #Chrome

Anyone been experimenting with this? The team are looking for feedback so we can decide on next steps. Would love to hear feedback (good or bad!) on this issue: github.com/WICG/nav-spe...

Add Prerender Until Script · Issue #305 · WICG/nav-speculation

We propose to add a third action called “preparse” (open for alternative names). Like prerendering, it fetches resources in advance; but unlike prerendering it does not execute JavaScript or render...

github.com

Barry Pollard@tunetheweb.com · 6mo ago

Think prefetch is not enough, but prerender is too risky for your site? Well then check out "prerender until script"—a new option we're testing for the Speculation Rules API now available for you to test on your site with an origin trial! developer.chrome.com/blog/prerend...

I built a free tool to analyze web performance: no login, no setup. Paste a URL → get an instant report on images, videos, page weight and third-party scripts. It's in beta. Try it 👇 #WebPerf #Performance #PerfInsights

Starting with Chrome 145, DevTools now lets you throttle specific requests instead of the whole page. It’s the ideal way to test how your app handles a single slow asset or API call → goo.gle/4aP1Tcc