Joan León Posts
All the articles I've posted.
Keep-Alive is not Cache-Control: anatomy of a network waterfall
Published: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.
The mystery of the self-repainting #document: Paint flashing and composited layers
Published:Why the #document layer racks up hundreds of repaints at rest because of a ticker animated with transform, how to catch it with the Layers tab and Paint flashing, and how to promote the element to its own composited layer with will-change.
Antigravity Skills: advanced YAML frontmatter configuration
Published:The kind, model, temperature, max_turns and tools fields in SKILL.md frontmatter let you precisely control how each agent runs in Antigravity. A practical guide to the extended fields that Google hasn't officially documented yet.
Video editing in the browser with WebGPU
Published:WebGPU enables real-time video effects and transformations in the browser. Practical implementation with benchmarks and real-world limitations.
Forced Synchronous Layout: how to detect and analyze it with DevTools
Published:How a scroll reset after mass DOM manipulation triggers a Forced Synchronous Layout, how to detect it in the Performance Panel and Selector Stats in Chrome DevTools, and how to fix it with requestAnimationFrame.
ML in the browser with WebGPU: real-time inference
Published:How to use WebGPU as the TensorFlow.js backend to run ML models in the browser with real performance. Benchmarks and practical use cases.
Automate the browser from the terminal with Chrome DevTools MCP CLI
Published: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 leaving the shell.
Image processing in the browser with WebGPU
Published:How to use WebGPU to apply filters and transformations to images in the browser. Real benchmarks comparing with Canvas 2D.