Deep dives
Cache headers, CDNs, and stale-while-revalidate
One header turns a cold cache into an instant page for roughly a third of visits, and it costs nothing to ship. What it does, and where it quietly breaks.
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Deep dives
Long reads that follow one mechanism all the way down. Slower to write, and the ones people still link to two years later.
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Deep dives
Reading a flame graph like a profiler would
Width is time and depth is the call stack. Once those two facts land, most of a trace reads itself.
Deep dives
The event loop, one frame at a time
Sixteen milliseconds, and everything that has to fit inside them before the screen updates.
Deep dives
How a browser decides what to paint
Invalidation, not repainting. The interesting work is in deciding how little to redo.
Deep dives
Inside the HTTP cache: a request’s whole journey
Memory cache, disk cache, service worker, CDN, origin. Five places a response can come from, and they disagree more often than you would like.
Deep dives
Fonts, from bytes to glyphs
Download, parse, match, shape, raster. The stage that surprises people is shaping, and it is the one you cannot skip.
Deep dives
What the compositor actually does
The last stage of the pipeline, running on its own thread, which is exactly why transform animations survive a busy main thread.
Deep dives
Memory in a long-lived single page app
The bug report says "it gets slow after a few hours". That is a leak, and the heap snapshot will name it.