Hi!

Welcome to this space where I share learnings about different topics related to the Front-end world, especially Web Performance.

Recent Posts

• A skill that knows nothing: the architecture of Modern Web Guidance

  Published:13 ago 2026

  Modern Web Guidance doesn't keep the knowledge in the skill, it teaches the agent to retrieve it. Local semantic search with MiniLM and TensorFlow.js, guides with their own grader, and empirical calibration of the content.

• The CrUX 28-day rolling window

  Published:11 ago 2026

  How the CrUX 28-day rolling window actually works, what each source publishes, and why p75 takes so long to move even though the data is only two days old.

• A 301 on every click: the trailing slash that slowed down all internal navigation

  Published:19 jul 2026

  A real finding on skills.addy.ie: every internal link triggered a 301 redirect on Netlify because of a missing trailing slash. What it costs the UX, how I spotted it in DevTools, the quick fix I first thought of, and the underlying solution (Astro directory format + trailingSlash: 'always'). With Network panel evidence before and after.

• Keep-Alive is not Cache-Control: anatomy of a network waterfall

  Published:2 jul 2026

  A real audit case: two heavy images (608 KB and 403 KB) over HTTP/1.1 with Connection: Keep-Alive but no Cache-Control. Why they are different things, what HTTP/2 fixes and how preconnect gets ahead of the handshake. With an interactive waterfall demo.